title: Opioids activate G proteins in REM sleep-related brain stem nuclei of rat.
abstract: Mu opioid receptors within the pontine reticular formation contribute to opioid-induced rapid eye movement (REM) sleep inhibition. Mu receptors are coupled to guanine nucleotide binding (G) proteins and this study tested the hypothesis that the micro opioid agonist [D-Ala2,N-Me-Phe4,Gly-ol5]enkephalin (DAMGO) would activate G proteins in rat brain stem nuclei known to regulate REM sleep. In vitro autoradiography of DAMGO-stimulated [35S]GTPgammaS binding showed that, compared with basal [35S]GTPgammaS binding, DAMGO significantly increased G protein activation in the nucleus pontis oralis (56.2%), nucleus pontis caudalis (57.3%), laterodorsal tegmental nucleus (75.8%), pedunculopontine tegmental nucleus (72.4%), nucleus locus coeruleus (77.2%) and dorsal raphe nucleus (73.4%). DAMGO stimulation of [35S]GTPgammaS binding in nuclei regulating REM sleep suggests that opioid-induced REM sleep inhibition involves activation of G proteins.
authors.affiliation: Department of Anesthesia, Pennsylvania State University College of Medicine, Hershey 17033, USA.
authors.forename: M L
authors.initials: ML
authors.lastname: Capece
authors.forename: H A
authors.initials: HA
authors.lastname: Baghdoyan
authors.forename: R
authors.initials: R
authors.lastname: Lydic
mesh_terms: D000818:Animals; D001345:Autoradiography / Q000379:methods; D001933:Brain Stem / Q000737:chemistry / Q000187:drug effects* / Q000502:physiology; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004745:Enkephalins / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000187:drug effects / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000032:analysis / Q000378:metabolism; D008297:Male; D009294:Narcotics / Q000494:pharmacology*; D011149:Pons / Q000737:chemistry / Q000187:drug effects / Q000502:physiology; D011485:Protein Binding; D051381:Rats; D017207:Rats, Sprague-Dawley; D017450:Receptors, Opioid, mu / Q000819:agonists; D012895:Sleep, REM / Q000502:physiology*; D013462:Sulfur Radioisotopes
chemical_list: D004745:Enkephalins; D009294:Narcotics; D017450:Receptors, Opioid, mu; D013462:Sulfur Radioisotopes; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D019204:GTP-Binding Proteins