Hormonal-neural integration in the female rat ventromedial hypothalamus: triple labeling for estrogen receptor-alpha, retrograde tract tracing from the periaqueductal gray, and mating-induced Fos expression.
The lordosis reflex, a stereotypic posture adopted by female rats during sexual behavior, requires the convergence of a hormonal signal, estrogen, with a descending neural pathway from the ventromedial hypothalamic nucleus (VMH). The VMH contains at least three lordosis-relevant neural populations: estrogen receptor-alpha immunoreactive (ERalpha-IR) neurons, VMH neurons that project to the periaqueductal gray (PAG), and neurons that are ERalpha-IR and project to the PAG. Expression of Fos, a marker for neuronal activation, is increased in the VMH after mating. However, it is unknown which, if any, of these lordosis-relevant populations is activated. The majority of ERalpha-IR and projection neurons were not colocalized. Of the Fos-positive neurons, 41% neither contained ERalpha nor projected to the PAG, and 35% contained ERalpha but did not project to the PAG. Only 25% of Fos-positive neurons projected to the PAG, including projection neurons that expressed ERalpha. Our results suggest that mating activates several distinct VMH neuron types. However, ERalpha-IR neurons are activated to a greater extent compared with the PAG-projecting neurons.
Calizo
Lyngine H
LH
Institute of Neurological Sciences, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Flanagan-Cato
Loretta M
LM
D000818:Animals; D047628:Estrogen Receptor alpha; D005260:Female; D005456:Fluorescent Dyes; D007150:Immunohistochemistry / Q000379:methods; D009434:Neural Pathways; D010487:Periaqueductal Gray / Q000166:cytology*; D011187:Posture; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011960:Receptors, Estrogen / Q000032:analysis / Q000502:physiology*; D012726:Sexual Behavior, Animal / Q000502:physiology*; D013266:Stilbamidines; D014697:Ventromedial Hypothalamic Nucleus / Q000737:chemistry / Q000166:cytology* / Q000502:physiology*
C049774:2-hydroxy-4,4'-diamidinostilbene, methanesulfonate salt; D047628:Estrogen Receptor alpha; D005456:Fluorescent Dyes; D016760:Proto-Oncogene Proteins c-fos; D011960:Receptors, Estrogen; D013266:Stilbamidines