Cytometric investigations in histochemically identified neurons--changes of fluorescence intensities and nuclear diameters in dopamine neurons of the arcuate nucleus in the cycling rat.
The relative formaldehyde-induced fluorescence intensities and the diameter of cell nuclei of fluorescent perikarya of the arcuate nucleus were recorded in serial cross-sectioned hypothalamic arcuate nuclei of regularly cycling rats (5 estrous and 4 proestrous animals). Stress-induced changes of cytometric parameters were avoided by preadaptation of animals to handling procedures. Dopamine neurons in a 75 micrometer thick periventricular layer of the arcuate nucleus exhibited significantly smaller nerve cell nuclei and significantly reduced relative fluorescence intensities in proestrous rats. Both of these cytometric parameters indicate a decrease in the activity of periventricular dopamine neurons of the arcuate nucleus. The reported findings might support the hypothesis that dopamine inhibits the release of LH-RH.
D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism / Q000648:ultrastructure*; D004298:Dopamine / Q000302:isolation & purification / Q000502:physiology; D004971:Estrus; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000037:antagonists & inhibitors / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000166:cytology*; D007620:Karyometry; D008473:Median Eminence / Q000166:cytology*; D009474:Neurons / Q000648:ultrastructure*; D011247:Pregnancy; D051381:Rats; D013050:Spectrometry, Fluorescence / Q000379:methods
D007987:Gonadotropin-Releasing Hormone; D004298:Dopamine