Wiley, Journal of Neuroendocrinology, 11(25), p. 1012-1023, 2013
DOI: 10.1111/jne.12103
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The acceptance of estradiol signaling through receptors found in the cell membrane, as well as, the nucleus has provided for a re-examination of timing and location of estradiol actions on neural circuits mediating sexual receptivity (lordosis). Estradiol membrane signaling involves the transactivation of metabotropic glutamate receptors (mGluR) that transduce steroid information through PKC signaling cascades producing rapid activation of lordosis regulating circuits. It has been known for some time that estradiol initially produces an inhibition of the medial preoptic nucleus (MPN). We have demonstrated that underlying this inhibition is estradiol acting in the arcuate nucleus to induce β-endorphin release which inhibits the MPN through a μ-opioid receptor mechanism. This transient inhibition is relieved by either subsequent progesterone treatment or longer exposure to higher doses of estradiol to facilitate lordosis behavior. We review recent findings about estradiol membrane signaling inducing dendritic spine formation in the arcuate nucleus that is critical for estradiol induction of sexual receptivity. Moreover, we discuss the evidence that in addition to ERα, several other putative membrane estrogen receptors facilitate lordosis behavior through regulation of the arcuate nucleus. These include the GRP30 and the STX activated Gq-mER. Finally, we report on the importance of GABA acting at GABAB receptors for estradiol membrane signaling that regulates lordosis circuit activation and sexual receptivity. This article is protected by copyright. All rights reserved.