Estrogen receptor-alpha and -beta immunoreactivity and mRNA in neurons of sensory and autonomic ganglia and spinal cord

Estrogen receptor-alpha immunoreactivity and mRNAs are present in neurons i n locales that innervate genital organs, e.g., parasympathetic pelvic auton omic ganglia, sensory dorsal root and nodose ganglia, and autonomic areas o f the lumbosacral spinal cord. With the availability of probes for the beta -isoform of the estrogen receptor, we studied this receptor in autonomic, sensory, and spinal cord neurons and compared it with the distribution of t he a-receptor. Estrogen receptor-alpha and -beta immunoreactivity were loca ted in the nuclei of neurons, were in subpopulations of parasympathetic neu rons in pelvic ganglia, and sensory neurons of dorsal root and nodose gangl ia. Both receptor subtypes were present in the lumbosacral spinal cord: in neurons of the outer laminae of the dorsal horn, lateral collateral and med ial collateral pathways, sacral parasympathetic nucleus, dorsal intermediat e gray, and lamina X. Similar numbers of spinal cord neurons were immunorea ctive for estrogen receptor-beta and estrogen receptor-alpha. However, estr ogen receptor-beta -immunoreactive neurons appeared less numerous in the ou ter dorsal horn, but more numerous in the deeper layers of the spinal cord than estrogen receptor-alpha neurons. Retrograde tracing from the uterus re vealed "uterine-related" neurons in dorsal root and pelvic ganglia that con tained estrogen receptor-alpha and -beta. In situ hybridization revealed bo th estrogen receptor-alpha and -beta mRNA transcripts in sensory neurons of the dorsal root and nodose ganglia, parasympathetic neurons of pelvic gang lia, and spinal cord neurons in the dorsal horn, sacral parasympathetic nuc leus, and dorsal intermediate gray of L6-S1 segments. These studies show th at both estrogen receptor-alpha and -beta are synthesized by autonomic and sensory neurons in parts of the nervous system that have connections with t he female reproductive system. Such neurons contain neurotransmitters that have important functions in the female reproductive organs; thus, it is lik ely that estrogen can influence the activity of such neurons and consequent ly, through them, the activities of the reproductive organs.