Tag Archives: Neurobiology

Identify the types of brain cells that may prompt men to fight and have sex | Instant News

A new study in rodents shows that two groups of nerve cells can act as “on-off switches” for males to mate and attack. These neurons seem to send signals between the two parts of the brain (the amygdala and the posterior or posterior part of the hypothalamus) to jointly regulate emotions including fear, anxiety, and aggression.

Led by researchers at New York University’s Grossman School of Medicine, this study showed that male mice had difficulty in intercourse during the experiment, which prevented a group of amygdala cells from communicating with the hypothalamus (MPN signaling cells). signal. On the contrary, when the same signal is enhanced, these animals are not only able to mate, but also repeatedly courting females that are unacceptable to females, which they usually cannot do.

Similarly, when the second cell population (VMHvl signaling cells) in the amygdala that also communicates with the hypothalamus is blocked, rodents attack unfamiliar males at half the frequency of the latter. When these same neurons are triggered, the mouse becomes abnormally aggressive, even attacking its female companions and familiar males.

Shan Gaolong, a postdoctoral researcher at New York University’s Langen School of Health and its Institute of Neuroscience, said: “Our findings provide new insights into the key role of the posterior amygdala in driving male sexual behaviors such as sexuality and aggressiveness.”

Past studies have shown the role of the amygdala in regulating social behavior, but until now, experts have not discovered its exact role in sexual behavior. Instead, the researchers focused on the hypothalamus, where both MPN and VMHvl structures are located, as a regulator of brain mating and fighting.

The new survey will be published online in the magazine on July 27 Natural NeuroscienceDr. Yamaguchi said that it was the first tissue to discover two different sets of cells that facilitate communication between the posterior amygdala and the responsible and aggressive part of the hypothalamus. He added that this also provides key evidence that the posterior part of the amygdala has a “huge” effect on social behavior.

In this study, the researchers observed the brain cell activity of more than 100 male mice that were mounted and fighting. The authors measured the frequency with which nerve cells naturally emit signals in animals throughout the day. They found that MPN signaling cells are most active during sex, while VMHvl signaling cells are most active when confronted with other males. Then, for each of these two cell groups, the researchers inhibited or activated neurons and observed how often the mice tried to partner with their partners or attack strange males placed in their enclosures.

Dr. Dayu Lin, associate professor and senior researcher at New York University Langen and its Institute of Neuroscience, said: “Our new understanding of which cells trigger sexual and aggressive behaviors will help us choose when designing future psychiatric treatments. A better brain target.”

Lin still warns that much of the structure of the amygdala is still poorly understood, and researchers still need to determine how these findings translate into the human brain. Her team also plans to study the interaction of two sets of nerve cells in the brains of female rodents.


The research was funded by R01MH101377, R21MH105774, R01HD092596 and U19NS107616 from the National Institutes of Health.

In addition to Yamaguchi and Lin, the other NYU Langone researchers involved in this study are Dr. Wei Dongyu; Soomin Song, Ph.D; and Dr. Nicolas Tritsch. Dr. Byungkook Lim of the University of California, San Diego provided support from other researchers.

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Shira Polan


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Does estrogen affect alcohol use disorders? | Instant News

PICTURE: Amy Lasek, professor of psychiatry and anatomy and cell biology, led the study, which specifically examined estrogen receptors in the brain to determine the mechanism used …
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Credit: UIC / Jenny Fontaine

A new study from researchers at the University of Illinois at Chicago shows that high estrogen levels can make alcohol more beneficial for female rats.

Study published in Journal of Neuroscience, suggesting that treatment for alcohol use disorders or binge drinking behavior might be more effective when considering gender differences.

Amy Lasek, professor of psychiatry and anatomy and cell biology, led the study, which specifically examined estrogen receptors in the brain to determine the mechanism of estrogen regulating alcohol sensitivity.

In one experiment, the researchers analyzed post-mortem brain tissue samples from female mice in two phases of the reproductive cycle – one marked with high estrogen levels and one marked with low estrogen levels. They activate estrogen receptors and track how dopamine neurons respond to alcohol.

“We found that when one estrogen receptor is activated – the alpha-neuron dopamine receptor fires at an increased rate in response to alcohol,” said Lasek, who is part of the UIC Alcohol Research Center at Epigenetics. “The effect is also greater in tissue taken from mice in the high estrogen phase.”

Lasek said that this increase in neural activity could translate into greater feelings of pleasure when drinking.

“This increased feeling of appreciation can make alcohol abuse, especially drinking behavior, more likely,” Lasek said.

In another experiment, the researchers blocked estrogen receptors located in the ventral tegmental area of ​​the brain – this is a region that is known to contain dopamine neurons and is associated with drug use – and tracked the behavior of female and male rats before them. alcohol.

They found that reducing the number of estrogen receptors, such as alpha estrogen receptors, causes a decrease in drinking behavior, but only in female mice.

“This is a new finding that suggests there may be a role for sex-specific estrogen receptors in the ventral tegmental area when it comes to alcohol use,” Lasek said.

“When we learn more about the role of estrogen in the brain’s sensitivity to the effects of alcohol, we might be able to develop treatments that are more specific to alcohol use disorders or can provide women with better education about how drinking can affect them differently during different stages of the reproductive cycle. they.

“This is very important because although more men are diagnosed with alcohol use disorders, around 5.3 million women in the US also suffer from alcohol use disorders,” Lasek said. “There is evidence that women transitioning more quickly from troubled alcoholic drinks to having alcohol use disorders and suffering negative health effects from alcohol, such as an increased risk of cancer, liver damage, heart disease, and brain damage.”


This study was supported with funding from the National Institute of Alcohol Abuse and Alcoholism (P50AA022538, U01 AA020912), the National Institute of Drug Abuse (R01DA033429) and the National Center for Advancing Translational Science (UL1TR002003).

UIC’s co-authors in this study were Bertha Vandegrift, Elisa Hilderbrand, Rosalba Satta, Rex Tai, Donghong He, Chang You, Hu Chen, Pingwen Xu, Cassandre Coles, and Mark Brodie.

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Early exposure to cannabis increases the sensitivity of young brains to cocaine, mouse research found | Instant News

NEW YORK – The use of cannabis makes young brains more sensitive to first exposure to cocaine, according to a new study in mice led by scientists at Columbia University and Cagliari University in Italy. By monitoring the brains of adolescent and adult mice after giving them synthetic psychoactive cannabinoids followed by cocaine, the research team identified key molecular and epigenetic changes that occur in adolescent brains – but not adults. This discovery reveals new interactions between two drugs that have never been directly observed in biological detail.

This finding, reported this week at Proceedings of the National Academy of Sciences, providing a new understanding of how cannabis abuse during adolescence can enhance firsts with cocaine and lead to sustainable use among vulnerable individuals.

“We know from human epidemiological studies that people who abuse cocaine have a history of early cannabis use, and that a person’s initial response to drugs can have a big impact on whether they continue to use it. But many questions remain about how early cannabis. Exposure affects the brain,” said Epidemiologist Denise Kandel, PhD, who is a professor of Sociomedical Sciences in Psychiatry at the College of Physicians and Vagelos Surgeons in Columbia and co-senior author of today’s paper.

“Our study in mice is the first to map detailed molecular and epigenetic mechanisms in which cocaine interacts with the brain that has been exposed to cannabinoids, providing much needed clarity on biological mechanisms that can increase the risk of drug abuse and addiction,” co added. – Nobel Prize Recipient Eric Kandel, MD, codirector of Mortimer B. Zuckerman Mind Behavior Institute, Columbia, and Senior Investigator Howard Hughes Medical Institute.

Previous research has revealed major differences in how cannabis and cocaine affect brain chemistry. “The study of the addictive nature of cocaine has traditionally focused on the mesolimbic dopaminergic pathway, the brain system that underlies our motivation to pursue pleasurable experiences,” said Philippe Melas, PhD, who is a research scientist at Eric Kandel’s laboratory at Zuckerman Institute’s laboratory in Columbia, Zuckerman Institute, Columbia. and is the co-senior author of this paper. “While cannabis increases mesolimbic dopaminergic activity similar to cocaine, it also affects an entirely different neurochemical system that is widespread in the brain called the endocannabinoid system. This system is very important for brain development – a process that is still ongoing in adolescence.”

Apart from the dopaminergic system, marijuana and cocaine seem to have some additional features. Recent studies have shown that the development of cocaine craving depends on the brain’s glutamatergic system. This system uses glutamate, a brain molecule that acts as a synaptic transmitter in the brain, increasing the transmission of signals between brain neurons. According to previous research, as well as the findings presented in new research today, the use of cannabis during adolescence can also influence this glutamatergic signaling process.

To dig deeper into the potential relationship between the two drugs, Dr. Melas and husband and wife team Drs. Eric and Denise Kandel partnered with Paola Fadda, PhD, Maria Scherma, PhD, and Walter Fratta, PhD, researchers in the Department of Biomedical Sciences, at the University of Cagliari in Italy. The group examined the behavioral, molecular and epigenetic changes that occur when juvenile and adult mice first experience WIN, a synthetic cannabinoid with psychoactive properties similar to THC found in cannabis, and then exposed to cocaine.

“We found that adolescent rats that had been previously exposed to WIN had an increased reaction to their initial exposure to cocaine. Specifically, we observed this effect in adult mice but not in adult mice,” Dr. researcher at the Department of Clinical Neuroscience at the Karolinska Institutet in Sweden.

After further examination, the team found that, when preceded by a history of use of psychoactive cannabinoids in adolescence, exposure to cocaine triggered a battery of unique molecular reactions in the rat brain. These reactions include not only the changes in the glutamate receptors mentioned above, but also the key epigenetic modifications. Epigenetic modifications are different, because they affect the way genes are turned on or off but do not affect the order of the genes themselves.

The Columbia team had previously discovered a similar epigenetic mechanism in adult animals in response to nicotine and alcohol in the brain’s appreciation center, known as nucleus accumbens. However, in this study, the epigenetic effects of canabinoids were found to be specific for adolescents and target the brain’s prefrontal cortex. The prefrontal cortex, which plays a role in a variety of executive functions, including long-term planning and self-control, is one of the last areas of the brain to reach maturity, a fact that has long been linked to teenagers’ propensity for risky behavior. .

In addition, deviant prefrontal cortex activity is often observed in patients suffering from addictions. Efforts to improve the function of the prefrontal cortex are currently being evaluated in the treatment of addictions through the use of brain stimulation and other methodologies.

“Our findings show that exposure to psychoactive cannabinoids during adolescence primed the prefrontal cortex of animals, so that the response to cocaine was different from animals that had been given cocaine without previously having experienced cannabis,” Dr. Weld.

These results in mice offer important clues to biological mechanisms that might underlie the way various classes of drugs can mutually reinforce in humans. These results also support the idea that cannabis abuse during adolescence can enhance a person’s initial positive experience with different drugs, such as cocaine, which in turn can have an effect on whether that person chooses to continue, or expand, their initial use of cocaine. .

“This study shows that adolescents who use marijuana may have favorable initial reactions to cocaine, which will increase the likelihood of them being involved in repeated use so that they eventually become addicted, especially if they carry additional environmental or genetic vulnerability,” Dr. Denise Kandel.

Most research involving mice and addictions has traditionally focused on adult animals. It is also largely limited to studying one substance of abuse at a time, without considering the history of drug exposure in adolescence.

“These and other experiments are the key to understanding the molecular changes to the brain that occur during drug use,” Dr. Eric Kandel, who is also a University Professor and Kavli Professor of Brain Sciences at Columbia. “This knowledge will be very important for developing effective treatments that reduce addiction by targeting the mechanisms underlying this disease.”


This paper is entitled “Exposure to Cannabinoids in adolescent rats reprogramming initial behavioral, molecular and epigenetic responses to cocaine.” Additional contributors include Johanna S. Qvist, Arun Asok, PhD, Shao-shan C. Huang, PhD, Paolo Masia, PhD, Matteo Deidda, PhD, Ya B. Wei, PhD and Rajesh K. Soni, PhD.

This research was supported by the Howard Hughes Medical Institute, Cohen Veterans Bioscience, Swedish Research Council (DN 350-2012-6535), Royal Physiographic Society in Lund (Sweden), Swedish-American Foundation, American National Institute of Mental Health (F32MH114306) and Project Department Biomedical Sciences in Italy (RICDIP_2012_Fratta_01).

The author states there is no conflict of interests.

Mortimer B. Zuckerman’s Mind Brain Behavior Institute from Columbia University brings together a group of world-class scientists and scholars to pursue the most pressing and interesting challenge of our time: understanding the brain and mind. A deeper understanding of the brain promises to change the health of humans and society. From effective treatments for disorders such as Alzheimer’s, Parkinson’s, depression and autism to advances in areas as fundamental to computer science, economics, law, the arts and social policy, the potential for humanity is staggering. To learn more, visit: zuckermaninstitute.columbia.edu.


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