Scientists pinpoint the brain center of the male libido

Scientists may have successfully spotted the brain center for the male libido responsible for sexual interest and mating in mouse models. The discovery may lead to improved drugs for sexual function.

This is according to a report by Medical Xpress published on Friday.

Senior researcher Dr. Nirao Shah, a professor of psychiatry and neurobiology at Stanford University School of Medicine, in California, said in the article that the newly-discovered region is responsible for recognizing the sex of other mice.

A desire to mate

"Aha, this is a female, maybe I can mate if she's willing," Shah explained according to the medical news outlet.

"That recognition is then transformed into the desire to mate and the act of mating by this circuit," he further noted. "Also, the circuit enables the behavior to be pleasurable so animals will seek to do it again, which is very important, because for a species to survive, animals need to reproduce."

In their previous work, the research team discovered that they could turn on and off male mice's recognition of an unfamiliar female mouse by toying with the neurons that communicate to the preoptic area of the hypothalamus (POA) from the amygdala, reported Medical Xpress.

"We had no reason to believe that this POA region would not only control the act of mating, but also regulate the desire to mate or regulate the pleasurable feelings elicited by mating," Shah said in the report.

"In principle, those three aspects of sexual behavior—the act of mating, the physical act itself, the urge to mate and the pleasure that accompanies it—those could be embodied in different brain regions," he noted. "But what we found is that the POA has these attributes."

Their new study brought to the surface a small set of so-called BNST neurons that are responsible for the secretion of a signaling protein called Substance P, noted Medical Xpress.

Increased sexual activity

When those neurons were stimulated, the male mice in the trials would proceed to go through a complete mating process - mounting, penetration and ejaculation -and would ejaculate a second time much more quickly than reported before the stimulation.

"It took one second or less for them to resume sexual activity," Shah said in a Stanford press release published on Friday. "That's a more than 400,000-fold reduction in the refractory period."

However, Shah added that “if you silence just this set of preoptic-hypothalamus neurons, the males don’t mate, period."

Shah further said in the statement that his research can now lead to new drugs related to sexual function.

“If these centers exist in humans — and now we know where to look — it should be possible to design small molecules that can be used to regulate these circuits,” Shah said.

“Such drugs would be quite different from today’s phosphodiesterase inhibitors,” which counter erectile dysfunction, Shah said. “Instead of generally enhancing blood flow in small vasculature throughout the body, they would directly amplify or tamp down a specific brain area that controls male sexual desire.”