Flickering candles, rose petals, smooth music, and… nothing? Many women who are premenopausal experience  inhibited sexual desire, or hypoactive sexual desire disorder, making physical intimacy seemingly impossible – and scientists are unclear as to why. As the drug touted as “the female Viagra” hit the market, researchers at the Wisconsin National Primate Research Center studied more about how the drug, called flibanserin, actually works, which may also lead to ways to improve its safety.

Dr. David Abbott, a professor of obstetrics and gynecology in the University of Wisconsin School of Medicine and Public Health, and Dr. Alexander Converse, associate scientist at UW–Madison’s Waisman Center, studied the effects of flibanserin in the common marmoset. Similar to humans, marmosets rely on pair bonding for mating success and family life. They also exhibit similar hormonal signaling activity and mating behaviors, especially in response to sexual cues such as touch and scent, providing an unparalleled model of the primate brain.

Scientists are especially interested in better understanding flibanserin due to its adverse side effects. These can be serious and include severely low blood pressure and potential loss of consciousness. In addition, alcohol consumption, certain medicines and liver impairment can exacerbate the risks.

To explore flibanserin’s effect on the brain, Abbott and Converse compared flibanserin-treated monkeys to untreated monkeys using noninvasive PET scanning on live common marmosets at the Wisconsin National Primate Research Center. After mapping the animals’ brains with MRI scans, Converse used PET imaging to correlate changes in brain chemistry, particularly the use of glucose at specific locations with flibanserin-induced behavioral changes. Together with colleague Yves Aubert, Converse and Abbott found glucose metabolism declined in the brain center linked to intimate grooming and solicitation of sex.

Study results link flibanserin-initiated decreases in female metabolism to increased pair bonding, meaning the bigger the metabolic dip in brain activity, the more grooming. Although both males and females in the study initiated more grooming, the behavior was more pronounced in the males, even though only females received the drug.

Although the female marmosets did not have hypoactive sexual desire disorder, the study nonetheless shows that flibanserin, by altering metabolic brain activity, prompts increased female behavior responses to grooming, a form of intimate, gentle touching from males. That, said Abbott, “offers the first insight into how the drug may be working in the brains of women.”

Reviewed August 2019

Kids can inherit their parents’ eye color, hair type, and even bone structure. But can genetics also explain a child’s anxiety levels? Researchers from the University of Wisconsin-Madison (UW) investigated whether there is a generational link for anxiety.

The study from UW’s Department of Psychiatry and the HealthEmotions Research Institute examined a large, multi-generational family of nearly 600 rhesus monkeys. Like humans, monkeys can become anxious when exposed to unfamiliar people, environment, or circumstances. In this study, monkeys were exposed to strangers who did not make eye contact – a situation that a human child may encounter.

During this situation, scientists used medical imaging methods commonly used on humans, including positron emission tomography (PET scans) exams, to identify the regions of the brain affected by anxiety. Once these medical images were taken, researchers compared brain activity within the rhesus family tree. The researchers found increased  activity across three parts of the brain 1) the amygdala, 2) the limbic brain fear center, and 3) the pre-frontal cortex.

“Over-activity of these three regions of the brain is directly linked to the later life risk to develop anxiety and depression,” said Dr. Ned Kalin, Wisconsin National Primate Research Center scientist and chair of psychiatry at the UW School of Medicine and Public Health. “This is a big step in understanding the neural underpinnings of inherited anxiety.”

This research marks a breakthrough in adolescent anxiety-related research, as it helps explain how genetics might affect brain function. Indeed, it was found that about 35% of anxiety tendencies can be explained by family history. Moreover, half of children who show extreme anxiety symptoms develop stress-related psychiatric disorders later in life.

“Now that we know where to look, we can develop a better understanding of the alterations that give rise to anxiety-related brain function,” Dr. Kalin said. “Our genes shape our brains to help make us who we are.”

Reviewed August 2019

Gender disparity is not only a matter of wages and family roles. Pulmonary disease can affect women differently, and with a greater degree of severity, than men.

Scientists like Dr. Kent Pinkerton, a Core Scientist in the California National Primate Research Center (CNPRC) Respiratory Diseases Unit and for the Inhalation Exposure Core at UC Davis, are utilizing nonhuman primate research to examine gender-based differences in lung health and disease and the effects of climate change on lung health. Since the nonhuman primate lung has been shown to have similar architectural, morphological and developmental patterns to that of humans, it is the perfect model of lung development and aging processes.

Dr. Pinkerton and his colleagues thoroughly reviewed sociocultural implications of pulmonary disease attributable to numerous causes, including biomass burning and infectious diseases among women in low-to middle-income countries, as well as disparities in respiratory health among sexual minority women in high-income countries. The scientific team sought answers to many questions – 10, to be exact – addressing gender-based disparities in lung health as it relates to telomere length, stages of life, hormones, cumulative effects, and environmental toxins.

For example, women in low- to middle-income countries must combat with household air pollution (HAP) or indoor air pollution from the indoor burning of solid fuels. With limited access to fuels, households often use wood, charcoal, animal waste, coal or crop residue for cooking using either open fires or traditional unvented stoves. These cooking fires release soot into the household air and blacken the interior walls, resulting in air that exceeds World Health Organization (WHO) air quality standards by 10 to 100 fold.

HAP exposure is linked to  four million deaths worldwide each year, predominantly from COPD, cardiovascular disease, acute pneumonia in children under age five and lung cancer. Bearing responsibility for cooking and childcare, women especially suffer from HAP exposure-related diseases.

Thankfully, cleaner cooking solutions, like highly efficient cookstoves or effective, well-maintained chimneys, can reduce household exposures and improve the health of women and kids worldwide. However, with a need to reach hundreds of millions of households and to find the best solutions and mechanisms to implement such strategies, the problem is daunting.

Utilizing the CNPRC’s extensive capabilities and resources, and a myriad of research projects under way, Dr. Pinkerton is well positioned to understand the mechanisms underlying respiratory diseases and to develop new strategies to alleviate the detrimental health outcomes of pollutant exposures.

Reviewed August 2019

A lock of hair – it’s not just a keepsake.

For the first time, researchers at the Wisconsin National Primate Research Center have proven an infant’s delicate hairs could reveal the hormonal environment to which the fetus was exposed during gestation. Their methods have significant implications for several fields, from neonatology to psychology, social science to neurology.

“We had this ‘Aha!’ realization that we could use hair in newborns, because it starts growing one to two months before birth,” said Dr. Christopher Coe, UW–Madison professor of psychology and director of the Harlow Center for Biological Psychology.

While hair closest to the scalp reveals more recent information, moving down the shaft effectively transits an individual’s hormonal timeline. For the noninvasive study, researchers took small samples of hair from mother rhesus monkeys and their infants, cleaned them and pulverized the hairs into a fine powder. Scientists then read the hormonal signature using a new mass spectrometry method.

Researchers were particularly interested in hormone differences in infants born to younger, first-time mothers versus more experienced mothers. To test their question, they compared monkey mothers equivalent in age to 15-year-old humans to older monkeys. Scientists have long known maternal age plays a role in pregnancy and delivery outcomes, but evidence suggested something more.

Prior studies have shown high levels of cortisol can impair reflexes and attention and increase incidence of emotional and learning problems. In the monkey study, researchers found that cortisone, an inactive form of cortisol, was higher in young mothers and in their babies than in hair of the older mothers and their infants.

Both Coe and Amita Kapoor, first author of this study and a researcher at the Wisconsin National Primate Research Center, are particularly interested in how maternal age affects the “maleness” and “femaleness” of babies. Additionally, babies born to young mothers also had higher levels of estrone (a form of estrogen) and testosterone in their hair than did babies born to older mothers. Levels of both these hormones were surprisingly similar between male and female infants, raising questions about everything from the significance of birth order to stereotypical “boy” and “girl” behaviors in children.

Scientists studying humans are “really excited because [this method] is so noninvasive,” Kapoor said. Next up? Scientists interested in performing similar tests on humans are looking for answers to a longstanding question – how come human babies aren’t quite as hairy as other primates?

Reviewed August 2019

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Photo credit: Kathy West for the California National Primate Research Center

Wildfires can can destroy a community, but it’s the smoke that can suck the life out of your lungs.  

But what exactly is smoke? Simply put – it’s a collection of particles suspended in the air as a result of a fire. And smoke from wildfires is a particularly complex assortment, with a greater quantity and variety of particles than smoke from other types of fire. It’s this combination that make wildfire smoke especially toxic to the lungs according to Kent Pinkerton, a researcher at the California National Primate Research Center and a professor of pediatrics and veterinary medicine.

“Particles and gases that are generated from wildfires can create all sorts of conditions and symptoms, such as tightness or pain in the chest, wheezing, shortness of breath, and coughing, all of which would be triggered in certain individuals,” said Pinkerton. “We may also see burning and stinging of the nose, eyes and throat, even dizziness or lightheadedness. Typically, we see a rapid recovery from symptoms, but there can be those for whom the symptoms linger for a day or 2.”

Children, in particular, are accurately susceptible to the negative effects of wildfire smoke.

“Children are always active and energetic and they take in large quantities of air with a rapid respiration rate. Because of this, the effects of the smoke can be far greater for children than for adults,” he explained. “Their lungs have a smaller surface area for the particles to interact with. Each of those can affect children to cause wheezing, coughing, shortness of breath that may not be evident in adults who are breathing the same air.”

Household pets can experience the same symptoms, but they also have one natural advantage over humans – a sophisticated filtering system.

“For mammals like cats and dogs, they have a very similar lung structure to humans.  They can also feel those effects just like we do,” Pinkerton said. “They also have the ability to protect themselves— they are more likely to be nose breathers rather than breathing through their mouths, which provides a certain degree of protection through the filtration of particles that are in the air through the nasal cavity. They have a much more complicated structure in the nasal cavity that we do as humans.”

Whether it’s kids or pets, wildfire smoke can be devastating to a respiratory system. But thanks to the continuing work of Pinkerton and his team of researchers, future smoke victims will likely live longer, healthier lives.

Reviewed August 2019

According to the Centers for Disease Control and Prevention (CDC), more than 1 in 10 U.S. school-aged kids have received an Attention Deficit Hyperactivity Disorder, or ADHD, diagnosis. That’s 6.4 million children who struggle with inattentiveness, hyperactivity, and – as Dr. Luis Populin from the University of Wisconsin (UW) studies – impulsive behavior.

“If you say to an impulsive child, ‘Do your homework so you will get a good grade at the end of the quarter,’ that has less appeal than ‘Let’s play baseball this afternoon instead of studying chemistry,’” said Dr. Populin, an associate professor of neuroscience at UW-Madison.

To measure impulsive behavior, Dr. Populin studied rhesus monkeys at the Wisconsin National Primate Research Center who showed signs of ADHD, measuring the effects of methylphenidate (or Ritalin, a common ADHD drug) on their working memory and other aspects of executive functioning.

In the study, monkeys who exhibited calmer behavior learned to wait for a larger, delayed reward, while monkeys who tended to fidget and act nervously always chose the immediate, but smaller incentive. This willingness to take a small reward right away, rather than wait for the larger, delayed reward is called “temporal discounting.”

However, when given doses of methylphenidate, both monkeys chose the delayed reward more frequently, improving the condition of temporal discounting – but perhaps impacting other areas of the brain.

Armed with this information, Dr. Populin hopes to devise a mathematical tool that will help a doctor choose the correct dosage to reduce a child’s impulsive behavior – but not hinder executive function skills.

To continue his research, Dr. Populin was awarded the prestigious Hartwell Individual Biomedical Research Award, which provides research funding for three years. With this funding, Dr. Populin and his team are continuing their study of ADHD, examining kid’s temporal discounting (also known as delay discount and time discounting) while playing computer games.

“We will test temporal discounting with a game that kids don’t see as boring, but is still able to evaluate impulsivity so the doctor can make a faster, more accurate dosage calculations,” said Dr. Populin. “Then everybody benefits.”