Neurons expressing estrogen receptor alpha differentially innervate the periaqueductal gray matter of female rats

Author(s)

Pacheco, Silvana da Silva ^{[1, 2]} ; Rondini, Tatiane Araujo ^[3] ; Bittencourt, Jackson Cioni ^[2] ; Elias, Carol Fuzeti ^{[4, 5]}

Affiliation

^[1] Univ Sao Paulo, Univ Hosp, BR-05508900 Sao Paulo, SP - Brazil

^[2] Univ Sao Paulo, Inst Biomed Sci, Dept Anat, Lab Chem Neuroanat, BR-05508900 Sao Paulo, SP - Brazil

^[3] Univ Nove de Julho, BR-01504001 Sao Paulo, SP - Brazil

^[4] Univ Michigan, Dept Mol & Integrat Physiol, Ann Arbor, MI 48109 - USA

^[5] Univ Michigan, Dept Obstet & Gynecol, Ann Arbor, MI 48109 - USA

• Document type: Journal article
• Source: Journal of Chemical Neuroanatomy; v. 97, p. 33-42, APR 2019.
• Web of Science Citations: 0

Abstract

The periaqueductal gray matter (PAG) is a brainstem site involved in distinct autonomic and behavioral responses. Among them, the motor control of female sexual behavior, including lordosis, is well described. Lordosis reflex is highly dependent on increasing levels of estradiol that occur in the afternoon of the proestrus day in normally cycling females. This effect is thought to be mediated primarily via actions in the ventromedial nucleus of the hypothalamus (VMH). By binding to estrogen receptor alpha (ER alpha), estradiol changes the activity of VMH neurons that project to the PAG. Evidence also exists for the coordination of PAG outputs by estradiolresponsive neurons outside the VMH. However, a comprehensive analysis of these circuitries is not available. Using stereotaxic injection of the retrograde tracer Fluorogold in distinct columns of the PAG we performed a systematic mapping of neurons innervating the PAG and those coexpressing ER alpha immunoreactivity. We found that the forebrain projections to PAG columns are largely segregated and that most of the ER alpha expressing neurons preferentially target the lateral and the ventrolateral columns. Dual labeled neurons were mostly found in the intermediate subdivision of the lateral septal nucleus, the posterior aspect of the medial bed nucleus of the stria terminalis, the medial preoptic nucleus, the striohypothalamic nucleus and the ventrolateral VMH. Few dual labeled neurons were also observed in the arcuate nucleus, in the posterodorsal subdivision of the medial nucleus of the amygdala and in the ventral premammillary nucleus. Our findings indicate that ER alpha modulates sexual behavior in female rats via an integrated neural network that differentially innervate the columns of the PAG. (AU)