Chapter 5. Hormones and the Brain

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By Freda Kreier The only cure to being drunk is to wait it out. But that might not always be the case: Injecting drunk mice with a naturally occurring hormone helped them sober up more quickly than they otherwise would have, a new study shows. Mice that received a shot of FGF21 — a hormone made by the liver — woke up from a drunken stupor roughly twice as fast as those that didn’t, researchers report in the March 7 Cell Metabolism. The find could one day be used to help treat alcohol poisoning, a sometimes-deadly side effect of heavy drinking that lands millions of people in the emergency room every year, says molecular endocrinologist David Mangelsdorf. The sobering effect of FGF21 isn’t the first time the hormone has been linked to drinking. Scientists have previously shown that livers ramp up production of this hormone when alcohol floods the bloodstream. And while FGF21 doesn’t help break down alcohol, researchers have found that the hormone can help protect livers from the toxic effects of liquor while dampening the desire to continue drinking in mice and monkeys. Those findings made Mangelsdorf, of the University of Texas Southwestern Medical Center in Dallas, and his colleagues curious whether FGF21 also plays a role in recovering from too much alcohol. So the team fed mice enough alcohol to knock them out and waited to see how long it took for them to wake up. © Society for Science & the Public 2000–2023.

Keyword: Drug Abuse; Hormones & Behavior
Link ID: 28711 - Posted: 03.23.2023

By Lisa Sanders, M.D. “It’s happening,” the 58-year-old man said quietly. Dr. Mark Chelmowski looked over to observe his patient. He was leaning forward, elbows on table, head propped up on his hands. Beads of sweat suddenly appeared on the man’s brow. More popped up on his cheeks, then his jaw. Rivulets ran down the contours of his face, then dripped off his chin onto the table. The man’s eyes were closed. He almost seemed asleep. Chelmowski said his name. “Yes, doctor” was the only response the normally chatty man gave. It was as if he were somehow distracted by the profound sweating. The patient’s vital signs were normal. He didn’t have a fever. His blood pressure and heart rate were normal. Throughout the exam, the patient sat quietly sweating. The collar, front and back of his shirt darkened. Then, as abruptly as it started, it was over. He opened his eyes and looked at Chelmowski. The patient could see the surprise in his doctor’s face. Chelmowski knew about his episodes of sweating — the two of them had been trying to figure them out for the past five months — but he had not yet witnessed one. The first time it happened, the patient was in his car on the way to the gym when suddenly he felt intensely hot. It was a bright July day in the Milwaukee area and seasonably warm. But this heat felt as if it came from inside his body. A vague prickling sensation spread down his face and neck to his chest and back. His heart seemed to speed up and then — pow — he was drenched in sweat. He turned the car around and headed home. He was describing the strange event to his partner when it happened again. And again. Each episode lasted only a couple of minutes, but it was strange. The sweating was so excessive. After a fourth episode, the patient’s partner insisted they go to the emergency room. He had another bout in front of the E.R. doctor, who immediately admitted him to the hospital. He was worried the patient might be having a heart attack. Profuse sweating often accompanies myocardial infarctions, the doctor told him. But it wasn’t his heart. He was discharged the next day and encouraged to follow up with his primary-care doctor. © 2023 The New York Times Company

Keyword: Epilepsy; Hormones & Behavior
Link ID: 28696 - Posted: 03.11.2023

By Azeen Ghorayshi For decades, male mice have been the default in scientific experiments that test new drugs or examine the connections of the brain. The reason? Female mice, which experience a four- to five-day cycle of fluctuating ovarian hormones, were thought to be too complicated. Accounting for the hormonal changes was viewed as too cumbersome and too expensive. But the estrous cycle has little to do with how female mice behave, according to a new study that used machine-learning software to track the second-to-second behavior of animals exploring an open space. Male mice actually exhibited more erratic behavior than females did. The study, published in the journal Current Biology on Tuesday, challenges century-old stereotypes that kept female animals out of laboratory research — and, until the 1990s, barred women from clinical trials. The new research is “tipping all of these assumptions about sex differences and the influence of hormones on their head,” said Rebecca Shansky, a behavioral neuroscientist at Northeastern University and a co-author of the new study. The cost of excluding females — whether human or animal — from scientific research is high. Women are almost twice as likely as men to experience severe side effects from drugs, most of which have dosages based on the initial testing done in men. Women also may not derive the same benefits from the drugs. Women “capable of becoming pregnant,” as the federal government put it, were largely excluded from clinical trials of drugs until 1993, when a new law required researchers funded by the National Institutes of Health to include women and minority groups. In the decades since, women have made up close to half of clinical research participants, though they still lag behind in studies of certain drugs, like those used to treat cardiovascular disease and psychiatric disorders. But a large sex gap persisted in basic science research using lab animals, studies that pave the way to medical breakthroughs. In neuroscience, according to a review published in 2010, studies of male lab animals outnumbered female ones by a factor of five. © 2023 The New York Times Company

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 28694 - Posted: 03.08.2023

By Susan Dominus For the past two or three years, many of my friends, women mostly in their early 50s, have found themselves in an unexpected state of suffering. The cause of their suffering was something they had in common, but that did not make it easier for them to figure out what to do about it, even though they knew it was coming: It was menopause. The symptoms they experienced were varied and intrusive. Some lost hours of sleep every night, disruptions that chipped away at their mood, their energy, the vast resources of good will that it takes to parent and to partner. One friend endured weeklong stretches of menstrual bleeding so heavy that she had to miss work. Another friend was plagued by as many as 10 hot flashes a day; a third was so troubled by her flights of anger, their intensity new to her, that she sat her 12-year-old son down to explain that she was not feeling right — that there was this thing called menopause and that she was going through it. Another felt a pervasive dryness in her skin, her nails, her throat, even her eyes — as if she were slowly calcifying. Then last year, I reached the same state of transition. Technically, it is known as perimenopause, the biologically chaotic phase leading up to a woman’s last period, when her reproductive cycle makes its final, faltering runs. The shift, which lasts, on average, four years, typically starts when women reach their late 40s, the point at which the egg-producing sacs of the ovaries start to plummet in number. In response, some hormones — among them estrogen and progesterone — spike and dip erratically, their usual signaling systems failing. During this time, a woman’s period may be much heavier or lighter than usual. As levels of estrogen, a crucial chemical messenger, trend downward, women are at higher risk for severe depressive symptoms. Bone loss accelerates. In women who have a genetic risk for Alzheimer’s disease, the first plaques are thought to form in the brain during this period. Women often gain weight quickly, or see it shift to their middles, as the body fights to hold onto the estrogen that abdominal fat cells produce. The body is in a temporary state of adjustment, even reinvention, like a machine that once ran on gas trying to adjust to solar power, challenged to find workarounds. © 2023 The New York Times Company

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 28658 - Posted: 02.08.2023

Heidi Ledford The humble prairie vole (Microtus ochrogaster) has long been revered for its unusual commitment to family. Pair-bonded couples huddle together, raise pups together and mate exclusively together — at least most of the time. Drop another couple’s pups into a cage with pair-bonded prairie voles and the adults will often foster those young as their own — highly unusual behaviour for a rodent. But a study published on 27 January in Neuron1 challenges decades of research that suggests a protein that detects the ‘love hormone’ oxytocin is responsible for the voles’ domestic bliss. Using CRISPR gene-editing, researchers found that prairie voles lacking the protein were still responsible parents and still formed monogamous relationships. These surprising results highlight the importance of revisiting accepted dogma when new scientific techniques emerge, says neuroscientist Bianca Jones Marlin at the Columbia University Zuckerman Institute in New York City. “Neuroscientists grew up in our field understanding that prairie voles pair bonded because of the distribution of oxytocin receptors and oxytocin,” she says. “That was canon.” For decades, neuroscientists interested in understanding the biological underpinnings of human social behaviours have been fascinated by prairie voles. “There’s a sort of eerie similarity between prairie vole social behaviours and human social behaviours,” says Nirao Shah, a neuroscientist at Stanford University in California. “Prairie voles are one of the few mammalian species that exhibit social attachment.” Social attachment The hormone oxytocin has long been thought to have a pivotal role in social behaviours. A protein that binds to oxytocin, called oxytocin receptor, is expressed differently in prairie vole brains than in the brains of other voles that do not form monogamous relationships. In humans, oxytocin levels rise in response to social interactions, and the hormone is important in stimulating uterine contractions during childbirth and the production of milk afterwards. © 2023 Springer Nature Limited

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 28653 - Posted: 02.01.2023

By Bonnie Berkowitz and  William Neff Creating a physique that can win at the highest level of professional bodybuilding requires superhuman self-discipline, intense training and genetic good fortune. Increasingly, say the people familiar with the culture and its consequences, it cannot be done without illicit drugs and a willingness to push a body to — or past — its limits. More than a dozen scientists, trainers, judges and competitors interviewed for this report said that just earning a pro card, an amateur’s ticket to the pro ranks, is very difficult without anabolic steroids. Winning a marquee title drug-free? Several people laughed at the question. “Impossible,” said Harrison Pope, one of the country’s leading anabolic-steroid researchers. The behemoths who win the best-known and most lucrative titles barely resemble the iconic, classically muscled champions of the past, such as Arnold Schwarzenegger, who won the sport’s premiere title, Mr. Olympia, seven times between 1970 and 1980. “Arnold Schwarzenegger would not win today,” said Brad Schoenfeld, a professor at Lehman College in New York and author of several books on bodybuilding and muscle growth. “He would not even get a pro card.” Although bodybuilders spend years lifting weights and honing each muscle, they don’t need to demonstrate strength for the judges beyond the ability to hold poses onstage. They only need to look strong. Some competitors — and a growing legion of young, mostly male admirers — chase that look by diving into a reckless pharmacological game of whack-a-mole that insiders say has grown more intense and dangerous as sheer size has trumped the “Greek god” ideal of previous generations.

Keyword: Hormones & Behavior; Drug Abuse
Link ID: 28588 - Posted: 12.10.2022

By Ingrid Wickelgren  Science has largely neglected pregnancy’s effect on the brain, even though it involves dramatic surges in steroid hormones, which are known to alter the organ. A decade ago neuroscientist Elseline Hoekzema, then a young postdoctoral fellow thinking about having her first child, and two of her female colleagues set out to bridge the knowledge gap. “There’s this enormous event involving such strong hormone changes,” says Hoekzema, now at Amsterdam University Medical Center. “It’s really weird that so little was known about this.” Their initial study, published in 2016, revealed for the first time that pregnancy produced significant structural changes in a woman’s brain that endured for at least two years after birth. Now in a new seven-year study, Hoekzema and her colleagues have seen the same structural changes in different women and have shown that pregnancy also alters the function of a key brain network involved in self-reflection. According to the work, which appeared on Nov. 22 in Nature Communications, the brain changes correlate with a mother’s enhanced bonding with her baby. The findings were derived from examining the female participants’ physiology and using questionnaires to assess their behavior and mental state. And for the first time in humans, the researchers found strong evidence that female hormones are behind it all. The biggest changes occur in a brain network that is active when the brain is idling—that is, when it is not engaged in any particular task—suggesting that pregnancy alters the organ’s baseline state. “[The researchers] are seeing these functional connectivity changes even at rest,” says Jodi Pawluski, a neuroscientist at the University of Rennes 1 in France, who studies the maternal brain and perinatal mental illness but was not involved in the study. “That speaks to the significance of this stage in a birthing person’s life and how it really is transformative in the brain.”

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 28566 - Posted: 11.23.2022

By Megan Twohey and Christina Jewett The medical guidance was direct. Eleven-year-old Emma Basques had identified as a girl since toddlerhood. Now, as she worried about male puberty starting, a Phoenix pediatrician advised: Take a drug to stop it. At 13, Jacy Chavira felt increasingly uncomfortable with her maturing body and was beginning to believe she was a boy. Use the drug, her endocrinologist in Southern California recommended, and puberty would be suspended. An 11-year-old in New York with deepening depression expressed a desire to no longer be a girl. A therapist told the family the drug was the preteen’s best option, and a local doctor agreed. “‘Puberty blockers really help kids like this,’” the child’s mother recalled the therapist saying. “It was presented as a tourniquet that would stop the hemorrhaging.” As the number of adolescents who identify as transgender grows, drugs known as puberty blockers have become the first line of intervention for the youngest ones seeking medical treatment. Their use is typically framed as a safe — and reversible — way to buy time to weigh a medical transition and avoid the anguish of growing into a body that feels wrong. Transgender adolescents suffer from disproportionately high rates of depression and other mental health issues. Studies show that the drugs have eased some patients’ gender dysphoria — a distress over the mismatch of their birth sex and gender identity. “Anxiety drains away,” said Dr. Norman Spack, who pioneered the use of puberty blockers for trans youth in the United States and is one of many physicians who believe the drugs can be lifesaving. “You can see these kids being so relieved.” But as an increasing number of adolescents identify as transgender — in the United States, an estimated 300,000 ages 13 to 17 and an untold number who are younger — concerns are growing among some medical professionals about the consequences of the drugs, a New York Times examination found. The questions are fueling government reviews in Europe, prompting a push for more research and leading some prominent specialists to reconsider at what age to prescribe them and for how long. A small number of doctors won’t recommend them at all. © 2022 The New York Times Company

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 28555 - Posted: 11.16.2022

By Rodrigo Pérez Ortega There’s clear evidence that racial discrimination negatively affects the health of people of color over the course of their lives. It’s associated with depression, anxiety, and psychological stress; it increases blood pressure; and it has been shown to weaken the immune system. However, few studies have linked single discriminatory events to immediate health effects. Now, data from a first-of-its-kind study suggest a racist attack could raise a person’s stress biomarkers almost immediately. “The big question mark, for me, has always been, how does this happen? What’s the black box that’s in the middle of discrimination, stress, and health disparities?” says Tiffany Yip, a developmental psychologist at Fordham University who was not involved with the study. “I think that this paper addresses that mechanistic question.” For the proof-of-concept study, Soohyun Nam at Yale University’s School of Nursing and her team collaborated with Black churches and their communities to recruit 12 Black people between the ages of 30 and 55 living in the northeastern United States. After accounting for the participants’ baseline stress levels, the research team adapted standardized survey questions about discrimination and microaggressions—such as whether they believed they had been mistaken for a service worker because of their race—and asked participants to share any occurrences of these experiences through a smartphone app. The method, known as ecological momentary assessment (EMA), has previously been used to study physical activity and behavior—such as alcohol intake reduction or smoking frequency. But this is one of the first studies correlating stress biomarkers and racist experiences using this precise monitoring technique. Researchers also asked the participants to describe their mood five times a day over the course of a week using the same phone app. To measure their biological response, participants spat into a tube four times a day over 4 days and froze the samples until research staff collected them. The researchers then had the samples analyzed in the lab to measure levels of cortisol, a hormone released during emotional distress, and alpha amylase, an enzyme that breaks down sugars and is secreted in stressful situations.

Keyword: Stress; Hormones & Behavior
Link ID: 28481 - Posted: 09.17.2022

Short ribs glazed in a sweet sticky sauce and slow-cooked to perfection, potato chips hand-fried and tossed with a generous coating of sour cream, chicken wings battered and double-fried so that they stay crispy for hours. What is it about these, and other, mouth-watering — but incredibly fatty — foods that makes us reach out, and keep coming back for more? How they taste on the tongue is one part of the story, but to really understand what drives “our insatiable appetite for fat,” we have to examine what happens after fat is consumed, says Columbia University’s Charles Zuker, a neuroscientist and molecular geneticist who has been a Howard Hughes Medical Institute (HHMI) Investigator since 1989. Two years ago, Zuker and his team reported how sugar, upon reaching the gut, triggers signals that are sent to the brain, thus fueling cravings for sweet treats. Now, in an article published in Nature on September 7, 2022, they describe a similar gut-to-brain circuit that underlies a preference for fat. “The gut is the source of our great desire for fat and sugar,” says Zuker. The topic in question is an incredibly timely one, given the current global obesity epidemic. An estimated 13 percent of adults worldwide are obese — thrice that in 1975. In the US, that figure is even higher — at a staggering 42 percent. “It’s a very significant and important health problem,” says Zuker. Having a high body-mass index is a risk factor for stroke, diabetes, and several other diseases. “It’s clear that if we want to help make a difference here, we need to understand the biological basis for our strong appetite for fat and sugar,” he says. Doing so will help us design interventions in the future to “suppress this strong drive to consume” and combat obesity.

Keyword: Obesity; Hormones & Behavior
Link ID: 28468 - Posted: 09.10.2022

By Gina Kolata Are you a man worried about your testosterone levels? Hoping to give them a boost? Tucker Carlson, the Fox News host, has a solution. A promotional video for a new installment in a video series by Mr. Carlson describes a “total collapse of testosterone levels in American men,” positing an explanation for what he and many conservatives see as a creeping loss of masculinity in today’s society. Chock-full of oiled, shirtless men performing vaguely masculine tasks, like turning over giant tires and throwing a javelin, the video has already been widely remarked upon on social media for its bizarre erotic imagery. But one shot in particular stands out: a naked man atop a rock pile, limbs outflung, exposing his genitals to the red light issuing from what appears to be a waist-high air purifier. Something very like the theme from “2001: A Space Odyssey” plays in the background. This is the treatment proposed by Mr. Carlson’s “documentary”: Revive your underperforming testicles with red light, in particular a device made by a little known company called Joovv. A leading endocrinologist says — no surprise — the whole thing is ridiculous, and not just because of the man receiving light therapy atop a pile of stone slabs in the dead of night. First, there is precious little evidence that testosterone “levels are declining by roughly 10 percent per decade, completely changing the way people are at the most fundamental level,” as Mr. Carlson has said. Studies examining changes in testosterone over time are challenging for several reasons, including difficulties in recruiting large populations of normal subjects, daily circadian changes in testosterone, and differences in testing methods over time, noted Dr. John Amory, an expert on male reproductive health at the University of Washington. © 2022 The New York Times Company

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 28298 - Posted: 04.23.2022

By Christina Caron Q: Are there any proven treatments for low libido in women? “Proven” is a strong word — and one that makes scientists squeamish. But it is safe to say that there is “very strong evidence” for increasing sexual desire through certain types of psychological interventions like cognitive behavioral therapy and mindfulness meditation, said Lori A. Brotto, a psychologist and professor at the University of British Columbia in Vancouver and a renowned expert in women’s sexual health. When it comes to medications, however, it’s a different story. In recent years, two new medications for women with low libido have been approved by the U.S. Food and Drug Administration, “though their efficacy is marginally better than a placebo,” said Dr. Stacy Tessler Lindau, a gynecologist at the University of Chicago Medicine and the creator of WomanLab, a website about sexual health. These drugs, flibanserin (a pill) and bremelanotide (an injection that is self-administered about 40 minutes before sexual activity), were approved for the “very small subset of women” who are premenopausal, have low libidos and do not have any identifiable physical, mental or relationship problems, Dr. Lindau said. “They may have modest benefit, but they also come with side effects and cost,” she added. “So far, insurance coverage has been limited.” In the end, the most beneficial solution will depend on the reason you are experiencing low libido and why you consider your libido to be a problem. For older women, loss of estrogen during menopause is commonly associated with a change in libido because it can cause vaginal dryness and tightness that can make intercourse painful. Some women also find it more difficult to get aroused. And when menopause is accompanied by hot flashes and night sweats, that can make sex seem less appealing too. © 2022 The New York Times Company

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 28235 - Posted: 03.11.2022

by Peter Hess Of all the brain chemistry that autism researchers study, few molecules have garnered as much attention as the so-called ‘social hormone,’ oxytocin. Some autistic children appear to have low blood levels of oxytocin, which has led several teams to test oxytocin delivered intranasally as an autism therapy. So far, though, such clinical trials have yielded inconsistent results. Here we explain what scientists know so far about oxytocin’s connection to autism. What does oxytocin do in the brain and body? Oxytocin serves multiple purposes, such as promoting trust between people, moderating our response to threats, and supporting lactation and mother-child bonding. The hormone is produced primarily in the hypothalamus, a brain region that mediates basic bodily functions, including hunger, thirst and body temperature. Oxytocin-producing neurons in the hypothalamus project into other parts of the brain, such as the nucleus accumbens, where the hormone regulates social-reward learning. In the brain’s sensory system, including the olfactory bulb, oxytocin seems to help balance excitatory and inhibitory signals, improving social-information processing, at least in rats. In the amygdala, oxytocin appears to help dull threat responses to negative social information and foster social recognition. The pituitary gland controls the release of oxytocin into the bloodstream. Blood oxytocin is crucial to start uterine muscle contractions during childbirth. It also supports lactation by facilitating the milk letdown reflex, stimulating the flow of milk into the nipple. © 2022 Simons Foundation

Keyword: Hormones & Behavior; Autism
Link ID: 28143 - Posted: 01.08.2022

By Pam Belluck What if something in the blood of an athlete could boost the brainpower of someone who doesn’t or can’t exercise? Could a protein that gets amplified when people exercise help stave off symptoms of Alzheimer’s and other memory disorders? That’s the tantalizing prospect raised by a new study in which researchers injected sedentary mice with blood from mice that ran for miles on exercise wheels, and found that the sedentary mice then did better on tests of learning and memory. The study, published Wednesday in the journal Nature, also found that the type of brain inflammation involved in Alzheimer’s and other neurological disorders was reduced in sedentary mice after they received their athletic counterparts’ blood. “We’re seeing an increasing number of studies where proteins from outside the brain that are made when you exercise get into the brain and are helpful for improving brain health, or even improving cognition and disease,” said Rudolph Tanzi, a professor of neurology at Massachusetts General Hospital and Harvard Medical School. He led a 2018 study that found that exercise helped the brains of mice engineered to have a version of Alzheimer’s. The most promising outcome would be if exercise-generated proteins can become the basis for treatments, experts said. The study, led by researchers at Stanford School of Medicine, found that one protein — clusterin, produced in the liver and in heart muscle cells — seemed to account for most of the anti-inflammatory effects. But several experts noted that recent studies have found benefits from other proteins. They also said more needs to be learned about clusterin, which plays a role in many diseases, including cancer, and may have negative effects in early stages of Alzheimer’s before brain inflammation becomes dominant. © 2021 The New York Times Company

Keyword: Alzheimers; Hormones & Behavior
Link ID: 28108 - Posted: 12.11.2021

by Angie Voyles Askham An intranasal form of the hormone oxytocin is no more effective than placebo at increasing social behaviors in autistic children, according to what may be the largest clinical trial of the treatment to date. The results were published today in The New England Journal of Medicine. Because of oxytocin’s role in strengthening social bonds, researchers have considered it as a candidate treatment for autism for more than a decade. Small trials hinted that the hormone could improve social skills in some autistic people, such as those with low blood levels of oxytocin or infants with Prader-Willi syndrome, an autism-related condition. But the new results, based on 250 autistic children, suggest that “oxytocin, at least in its current form, is probably not helpful for the majority of kids with autism,” says Evdokia Anagnostou, professor of pediatrics at University of Toronto in Canada, who was not involved in the new work. The null results “change things,” says lead researcher Linmarie Sikich, associate professor of psychiatry and behavioral sciences at the Duke Center for Autism and Brain Development in Durham, North Carolina. “Most people still felt like there was a good chance that this would be treatment for many people with autism.” This type of research is prone to publication bias, in which non-significant results are less likely to be published than significant ones, says Daniel Quintana, senior researcher in biological psychiatry at the University of Oslo in Norway, who was not involved in the study. For that reason, the new work is “an important contribution to the field,” he says, but “it does not alone put to rest the idea of using intranasal oxytocin as an autism treatment.” © 2021 Simons Foundation

Keyword: Autism; Hormones & Behavior
Link ID: 28036 - Posted: 10.16.2021

Sophie Fessl The hormone irisin is necessary for the cognitive benefits of exercise in healthy mice and can rescue cognitive decline associated with Alzheimer’s disease, according to a study published August 20 in Nature Metabolism. According to the authors, these results support the hypothesis that irisin undergirds the cognitive benefits of exercise—a link that has been long debated. In addition, this study has “paved the way for thinking whether irisin could be a therapeutic agent against Alzheimer’s disease,” says biologist Steffen Maak with the Leibniz Institute for Farm Animal Biology in Germany, who has been critical of the methods used to study irisin in the past and was not involved in the study. Many studies have found that exercise is good for the brain, but the molecular mechanisms responsible for the cognitive boost have remained elusive. During her postdoctoral studies, neuroscientist Christiane Wrann found that the gene that codes for irisin becomes highly expressed in the brain during exercise—one of the first studies linking irisin with the brain. See “Irisin Skepticism Goes Way Back” When she joined the faculties at Massachusetts General Hospital and Harvard Medical School, she decided to investigate the hormone further. Wrann, who holds a patent related to irisin and is academic cofounder and consultant for Aevum Therapeutics, a company developing drugs that harness the protective molecular mechanisms of exercise to treat neurodegenerative and neuromuscular disorders, began to investigate whether irisin mediates the positive effects of exercise on the brain. © 1986–2021 The Scientist.

Keyword: Learning & Memory; Hormones & Behavior
Link ID: 27985 - Posted: 09.13.2021

By Lisa Sanders, M.D. The young woman was awakened by the screams of her 39-year-old husband. “Please make it stop!” he shouted, leaping from the bed. “It hurts!” He paced back and forth across the room, arms crossed over his chest as if to protect himself. Two days earlier, he had inhaled a breath mint when his wife startled him. He felt it move slowly down his throat as he swallowed repeatedly. His chest had hurt ever since. But not like this. The man squirmed miserably throughout the short drive to the emergency room at Westerly Hospital, near the Rhode Island and Connecticut border. No position was comfortable. Everything hurt. Even breathing was hard. Although the doctors in the E.R. immediately determined that the young man wasn’t having a heart attack, it was clear something was very wrong. His blood pressure was so low that it was hard to measure. A normal blood pressure may be 120/80. On arrival, his was 63/32. With a pressure this low, blood couldn’t get everywhere it was needed — a condition known as shock. His lips, hands and feet had a dusky hue from this lack of well-​oxygenated blood. He was given intravenous fluids to bring up his pressure, and when that didn’t work, he was started on medications for it. Three hours later, he was on two of these medicines and his fourth liter of fluid. Despite that, his pressure remained in the 70s. He had to be put on a breathing machine to help him keep up with his body’s demand for more oxygen. The most common cause of shock is infection. But this man, as sick as he was, had no signs of infection. The medical team started him on antibiotics anyway. Could the painful mint have torn his esophagus? Up to 50 percent of patients with that injury will die. A CT scan showed no evidence of perforation or of fluid in his chest. What else could this be? There was no sign of a clot keeping blood from entering the lungs, another cause of deadly low blood pressure. An ultrasound of the heart showed that he had some fluid in the sac called the pericardium, which contains and protects the heart, but not enough to interfere with how well it was beating. He was tested for Covid and for recreational drugs — both negative. © 2021 The New York Times Company

Keyword: Hormones & Behavior; Neuroimmunology
Link ID: 27981 - Posted: 09.08.2021

by Angie Voyles Askham Male mice exposed to atypically low levels of a placental hormone in the womb have altered brain development and asocial behaviors, according to a new study. The findings may help explain why preterm birth — which coincides with a deficiency in hormones made by the placenta — is linked to an increased likelihood of having autism. The hormone, called allopregnanolone, crosses the blood-brain barrier, binds to receptors for the chemical messenger gamma-aminobutyric acid (GABA) and helps regulate aspects of neurodevelopment, including the growth of new neurons. Its levels typically peak in the fetus during the second half of gestation. In the new study, researchers engineered a mouse model to have low fetal levels of allopregnanolone, mimicking the hormone’s loss due to preterm birth or placental dysfunction. The male mice in particular have structural changes in the cerebellum, a brain region known for balance and motor control, and exhibit more pronounced autism-like traits than control mice or female model mice. The new model “has a good translational potential for understanding the underlying mechanisms of sex differences in neurodevelopmental conditions such as autism,” says Amanda Kentner, professor of psychology at the Massachusetts College of Pharmacy and Health Sciences in Boston, who was not involved in the work. Injecting a pregnant mouse with allopregnanolone partway through gestation decreased the likelihood that its offspring would have autism-like traits, the researchers found. © 2021 Simons Foundation

Keyword: Autism; Development of the Brain
Link ID: 27977 - Posted: 09.04.2021

By Gretchen Reynolds An intriguing new study shows how exercise may bolster brain health. The study was in mice, but it found that a hormone produced by muscles during exercise can cross into the brain and enhance the health and function of neurons, improving thinking and memory in both healthy animals and those with a rodent version of Alzheimer’s disease. Earlier research shows that people produce the same hormone during exercise, and together the findings suggest that moving could alter the trajectory of memory loss in aging and dementia. We have plenty of evidence already that exercise is good for the brain. Studies in both people and animals show that exercise prompts the creation of new neurons in the brain’s memory center and then helps those new cells survive, mature and integrate into the brain’s neural network, where they can aid in thinking and remembering. Large-scale epidemiological studies also indicate that active people tend to be far less likely to develop Alzheimer’s disease and other forms of dementia than people who rarely exercise. But how does working out affect the inner workings of our brains at a molecular level? Scientists have speculated that exercise might directly change the biochemical environment inside the brain, without involving muscles. Alternatively, the muscles and other tissues might release substances during physical activity that travel to the brain and jump-start processes there, leading to the subsequent improvements in brain health. But in that case, the substances would have to be able to pass through the protective and mostly impermeable blood-brain barrier that separates our brains from the rest of our bodies. Those tangled issues were of particular interest a decade ago to a large group of scientists at Harvard Medical School and other institutions. In 2012, some of these researchers, led by Bruce M. Spiegelman, the Stanley J. Korsmeyer Professor of Cell Biology and Medicine at the Dana-Farber Cancer Institute and Harvard Medical School, identified a previously unknown hormone produced in the muscles of lab rodents and people during exercise and then released into the bloodstream. They named the new hormone irisin, after the messenger god Iris in Greek mythology. © 2021 The New York Times Company

Keyword: Learning & Memory; Muscles
Link ID: 27961 - Posted: 08.25.2021

By Kim Tingley During menopause, which marks the end of a woman’s menstrual cycles, her ovaries stop producing the hormones estrogen and progesterone, bringing an end to her natural childbearing years. But those hormones also regulate how the brain functions, and the brain governs their release — meaning that menopause is a neurological process as well. “Many of the symptoms of menopause cannot possibly be directly produced by the ovaries, if you think about the hot flashes, the night sweats, the anxiety, the depression, the insomnia, the brain fog,” says Lisa Mosconi, an associate professor of neurology at Weill Cornell Medicine and director of its Women’s Brain Initiative. “Those are brain symptoms, and we should look at the brain as something that is impacted by menopause at least as much as your ovaries are.” In June, Mosconi and her colleagues published in the journal Scientific Reports one of the few studies to observe in detail what happens to the brain throughout the menopause transition, not just before and after. Using various neuroimaging techniques, they scanned the brains of more than 160 women between the ages of 40 and 65 who were in different stages of the transition to examine the organ’s structure, blood flow, metabolism and function; they did many of the same scans two years later. They also imaged the brains of men in the same age range. “What we found in women and not in men is that the brain changes quite a lot,” Mosconi says. “The transition of menopause really leads to a whole remodeling.” On average, women in the United States enter the menopause transition — defined as the first 12 consecutive months without a period — at around 50; once diagnosed, they are in postmenopause. But they may begin to have hormonal fluctuations in their 40s. (For some women, this happens in their 30s, and surgical removal of the ovaries causes immediate menopause, as do some cancer treatments.) Those fluctuations cause irregular periods and potentially a wide variety of symptoms, including hot flashes, insomnia, mood swings, trouble concentrating and changes in sexual arousal. During this phase, known as perimenopause, which averages four years in length (but can last from several months to a decade), Mosconi and colleagues observed that their female subjects experienced a loss of both gray matter (the brain cells that process information) and white matter (the fibers that connect those cells). Postmenopause, however, that loss stopped, and in some cases brain volume increased, though not to its premenopausal size. © 2021 The New York Times Company

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 27917 - Posted: 07.21.2021