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Titolo:
Opioids suppress IPSCs in neurons of the rat medial septum/diagonal band of Broca: Involvement of mu-opioid receptors and septohippocampal GABAergic neurons
Autore:
Alreja, M; Shanabrough, M; Liu, WM; Leranth, C;
Indirizzi:
Yale Univ, Sch Med, Dept Psychiat, New Haven, CT 06508 USA Yale Univ New Haven CT USA 06508 , Dept Psychiat, New Haven, CT 06508 USA Yale Univ, Sch Med, Dept Obstet & Gynecol, New Haven, CT 06508 USA Yale Univ New Haven CT USA 06508 bstet & Gynecol, New Haven, CT 06508 USA Yale Univ, Sch Med, Dept Neurobiol, New Haven, CT 06508 USA Yale Univ NewHaven CT USA 06508 Dept Neurobiol, New Haven, CT 06508 USA Connecticut Mental Hlth Ctr, Abraham Ribicoff Res Facil, New Haven, CT 06519 USA Connecticut Mental Hlth Ctr New Haven CT USA 06519 ew Haven, CT 06519 USA
Titolo Testata:
JOURNAL OF NEUROSCIENCE
fascicolo: 3, volume: 20, anno: 2000,
pagine: 1179 - 1189
SICI:
0270-6474(20000201)20:3<1179:OSIINO>2.0.ZU;2-7
Fonte:
ISI
Lingua:
ENG
Soggetto:
HIPPOCAMPAL PYRAMIDAL CELLS; DIAGONAL BAND; CHOLINERGIC NEURONS; GUINEA-PIG; INHIBITORY INTERNEURONS; POSITIVE NEURONS; BETA-ENDORPHIN; MESSENGER-RNA; DENTATE GYRUS; SEPTUM;
Keywords:
septohippocampal; GABA; opioids; parvalbumin; septum; diagonal band of Broca;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
48
Recensione:
Indirizzi per estratti:
Indirizzo: Alreja, M Yale Univ, Sch Med, Dept Psychiat, CMHC 335,34 Pk St, New Haven,CT 06508 USA Yale Univ CMHC 335,34 Pk St New Haven CT USA 06508 CT 06508 USA
Citazione:
M. Alreja et al., "Opioids suppress IPSCs in neurons of the rat medial septum/diagonal band of Broca: Involvement of mu-opioid receptors and septohippocampal GABAergic neurons", J NEUROSC, 20(3), 2000, pp. 1179-1189

Abstract

The medial septum/diagonal band region (MSDB), which provides a major cholinergic and GABAergic input to the hippocampus, expresses a high density ofopioid receptors. Behaviorally, intraseptal injections of opioids produce deficits in spatial memory, however, little is known about the electrophysiological effects of opioids on MSDB neurons. Therefore, we investigated theelectrophysiological effects of opioids on neurons of the MSDB using rat brain slices. In voltage-clamp recordings with patch electrodes, bath-applied met-enkephalin, a nonselective opioid receptor agonist, decreased the number of tetrodotoxin and bicuculline-sensitive inhibitory synaptic currents in cholinergic- and GABA-type MSDB neurons. A similar effect occurred in brain slices containing only the MSDB, suggesting that opioids decrease GABA release primarily by inhibiting spontaneously firing GABAergic neurons located within the MSDB. Accordingly, in extracellular recordings, opioid-sensitive, spontaneously firing neurons could be found within the MSDB. Additionally, in intracellular recordings a subpopulation of GABA-type neurons weredirectly inhibited by opioids. All effects of met-enkephalin were mimickedby a mu receptor agonist, but not by delta or kappa agonists. In antidromic activation studies, mu-opioids inhibited a subpopulation of septohippocampal neurons with high conduction velocity fibers, suggestive of thickly myelinated GABAergic fibers. Consistent with the electrophysiological findings, in double-immunolabeling studies, 20% of parvalbumin-containing septohippocampal GABA neurons colocalized the m receptor, which at the ultrastructural level, was found to be associated with the neuronal cell membrane. Thus,opioids, via mu receptors, inhibit a subpopulation of MSDB GABAergic neurons that not only make local connections with both cholinergic and noncholinergic-type MSDB neurons, but also project to the hippocampus.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/04/20 alle ore 00:30:01