Research led by LSU Biological Sciences Associate Professor Ryoichi Teruyama has found neurons with oxytocin receptors that are exclusive to female mice.
These neurons were located in the medial preoptic area of the brain, which Teruyama said is known to regulate maternal behavior.
“Our hypothesis is that the cells in this part of the brain make up a neural-circuit unique to women that regulates maternal instinct,” Teruyama said.
Teruyama has previously led a project studying the neuroanatomy of alligators. Seeking a fully labeled 3-D reconstruction, his undergraduate researchers sectioned and stained the brains before taking detailed images. The team also compared their samples to avian brains, as the two are closely related.
Now, research led by LSU associate professor Ryoichi Teruyama has found neurons with oxytocin receptors that are exclusive to female mice. These neurons were located in the medial preoptic area of the brain, which Teruyama said is known to regulate maternal behavior. “Our hypothesis is that the cells in this part of the brain make up a neural-circuit unique to women that regulates maternal instinct.”
Oxytocin is a hormone found in a large variety of animals. It is normally produced by the brain’s hypothalamus and released by the pituitary gland. Though often prescribed to induce contractions for facilitating childbirth, oxytocin acts as an excitatory neurotransmitter, and is sometimes called the love drug for its importance in reproduction and social behavior. “Oxytocin is absolutely needed for you to behave socially,” Teruyama stressed.
Teruyama’s research has located a difference in oxytocin use between males and females but it also revealed that the presence of oxytocin receptors in these cells is dependent on estrogen, a female sex hormone. Researchers demonstrated that upon removing the mice’s ovaries, which is the primary source of estrogen, neurons stopped expressing receptors for oxytocin. Receptor expression resumed upon injecting estrogen.
This may be mirrored in pregnant human women. During pregnancy estrogen levels are supressed while the levels of another sex hormone, progesterone, rise. Normal levels of both hormones resume at birth.
Oxytocin’s suspected roles throughout the body are numerous and varied, and because of its antidepressant-like effects, this discovery may shed some light on the nature of postpartum depression, which can severely affect both mother and child.
Although nothing has been confirmed Teruyama said he thinks this discovery isn’t exclusive to mice and that it could apply to all mammals.
“Many researchers have attempted to investigate the difference between the oxytocin system in females versus males, but no one has found conclusive evidence until now,” Teruyama said in a statement.
Last week the project received funding from National Institute of Health, so research will continue for at least two more years.
