Serotonin and norepinephrine uptake in discrete brain regions during the pregnant mare serum (PMS) induced estrous cycle in the rat.
The role of hypothalamic and limbic aminergic systems in neuroendocrine control in the rat has been investigated by measuring the temporal changes in serotonergic and noradrenergic neuronal uptake in a model of the estrous cycle. Using the pregnant mare serum (PMS) model of induced ovulation and an in vitro uptake system, serotonergic activity reached peak values (p = 0.01) in the suprachiasmatic nuclear region (SNR) and median eminence (ME) (p = 0.007) during the critical period for luteinizing hormone release. 5, 7-dihydroxytryptamine lesions of the SNR or ME regions inhibited PMS induced ovulation suggesting that at least in these two areas a certain amplitude of 5-HT activity may be required at some time prior to the critical period for LH release. Serotonergic uptake during diestrus in the median eminence showed maximum values during the mid-light phase suggesting a role for this region in ovulation control mechanisms prior to the proestrous critical period. Significant changes (p = 0.001) in serotonergic uptake were found in mid to later light diestrus in the amygdala. This pattern was repeated during proestrus and estrus only in the amygdala suggesting a daily pattern of serotonergic uptake during the estrous cycle. Significant changes (p = 0.001) in noradrenergic uptake only occurred in the amygdala during proestrus.
D000818:Animals; D001921:Brain / Q000378:metabolism*; D004971:Estrus / Q000187:drug effects*; D005260:Female; D006064:Gonadotropins, Equine / Q000494:pharmacology*; D066298:In Vitro Techniques; D009638:Norepinephrine / Q000378:metabolism*; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000378:metabolism*; D013997:Time Factors; D014018:Tissue Distribution
D006064:Gonadotropins, Equine; D012701:Serotonin; D009638:Norepinephrine