Open AccessOxytocin Neurons Enable Melanocortin Regulation of Male Sexual Function in Mice
Author(s) -
Erin Semple,
Firas Shalabi,
Jennifer W. Hill
Publication year - 2019
Publication title -
molecular neurobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.569
H-Index - 111
eISSN - 1559-1182
pISSN - 0893-7648
DOI - 10.1007/s12035-019-1514-5
Subject(s) - melanocortin , melanocortin 4 receptor , ejaculation , endocrinology , medicine , melanocortins , biology , oxytocin , sexual function , neuroscience , hormone
The melanocortin pathway has been implicated in both metabolism and sexual function. When the melanocortin 4 receptor (MC4R) is knocked out globally, male mice display obesity, low sexual desire, and copulatory difficulties; however, it is unclear whether these phenotypes are interdependent. To elucidate the neuronal circuitry involved in sexual dysfunction in MC4R knockouts, we re-expressed the MC4R in these mice exclusively on Sim1 neurons (tbMC4R Sim1 mice) or on a subset of Sim1 neurons, namely oxytocin neurons (tbMC4R oxt mice). The groups were matched at young ages to control for the effects of obesity. Interestingly, young MC4R null mice had no deficits in sexual motivation or erectile function. However, MC4R null mice were found to have an increased latency to reach ejaculation compared to control mice, which was restored in both tbMC4R Sim1 and tbMC4R oxt mice. These results indicate that melanocortin signaling via the MC4R on oxytocin neurons is important for normal ejaculation independent of the male's metabolic health.