title: mu-Opioid agonist-stimulated [35S]GTPgammaS binding in guinea pig hypothalamus: effects of estrogen.
abstract: mu-Opioid receptors play a critical role in the regulation of the female reproductive cycle, and estrogen modulates the coupling of mu-opioid receptors to a potassium channel in the basal hypothalamus (BH) of the female guinea pig. Therefore, we ascertained the distribution of mu-opioid receptors in the BH with autoradiography using the mu-opioid selective agonist [3H]DAMGO. In addition, we investigated the effects of estrogen on DAMGO- or the GABAB receptor agonist baclofen-stimulated [35S]GTPgammaS binding in the BH. Based on the high density of mu-opioid receptors, but the lack of effects of estrogen on [35S]GTPgammaS binding, we conclude that mu-opioid receptor interaction with its G-protein is not the target of estrogen's actions.
authors.affiliation: Department of Physiology and Pharmacology, L334, Oregon Health Sciences University, Portland, OR 97201, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Cunningham
authors.forename: Y
authors.initials: Y
authors.lastname: Fang
authors.forename: D E
authors.initials: DE
authors.lastname: Selley
authors.forename: M J
authors.initials: MJ
authors.lastname: Kelly
mesh_terms: D000818:Animals; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004745:Enkephalins / Q000378:metabolism / Q000494:pharmacology*; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism*; D006168:Guinea Pigs; D007031:Hypothalamus / Q000187:drug effects* / Q000378:metabolism; D009490:Neurosecretory Systems / Q000187:drug effects; D015221:Potassium Channels / Q000187:drug effects; D011869:Radioligand Assay; D017450:Receptors, Opioid, mu / Q000819:agonists*; D013268:Stimulation, Chemical; D013462:Sulfur Radioisotopes
chemical_list: D004745:Enkephalins; D004967:Estrogens; D015221:Potassium Channels; D017450:Receptors, Opioid, mu; D013462:Sulfur Radioisotopes; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D016244:Guanosine 5'-O-(3-Thiotriphosphate)