Prostaglandin E2 receptor Ptger4b regulates female-specific peptidergic neurons and female sexual receptivity in medaka

In vertebrates, female receptivity to male courtship is highly dependent on ovarian secretion of estrogens and prostaglandins. We recently identified female-specific neurons in the medaka ( Oryzias latipes ) preoptic area that express Npba, a neuropeptide mediating female sexual receptivity, in response to ovarian estrogens. Here we show by transcriptomic analysis that these neurons express a multitude of neuropeptides, in addition to Npba, in an ovarian-dependent manner, and we thus termed them female-specific, sex steroid-responsive peptidergic (FeSP) neurons. Our results further revealed that FeSP neurons express a prostaglandin E 2 receptor gene, ptger4b , in an ovarian estrogen-dependent manner. Behavioral and physiological examination of ptger4b -deficient female medaka found that they exhibit increased sexual receptivity while retaining normal ovarian function and that their FeSP neurons have reduced firing activity and impaired neuropeptide release. Collectively, this work provides evidence that prostaglandin E 2 /Ptger4b signaling mediates the estrogenic regulation of FeSP neuron activity and female sexual receptivity. Prostaglandin E 2 signaling mediates the estrogenic regulation of peptidergic neuronal activity and female receptivity via the ptger4b gene pathway in Japanese rice fish.