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Titolo:
Effects of the endogenous opioid peptide, endomorphin 1, on supraoptic nucleus oxytocin and vasopressin neurones in vivo and in vitro
Autore:
Doi, N; Brown, CH; Cohen, HD; Leng, G; Russell, JA;
Indirizzi:
Univ Edinburgh, Sch Med, Dept Biomed Sci, Edinburgh EH8 9XD, Midlothian, Scotland Univ Edinburgh Edinburgh Midlothian Scotland EH8 9XD Midlothian, Scotland Kaken Pharmaceut Co Ltd, Dev Res Lab, Kyoto 607, Japan Kaken Pharmaceut CoLtd Kyoto Japan 607 d, Dev Res Lab, Kyoto 607, Japan
Titolo Testata:
BRITISH JOURNAL OF PHARMACOLOGY
fascicolo: 5, volume: 132, anno: 2001,
pagine: 1136 - 1144
SICI:
0007-1188(200103)132:5<1136:EOTEOP>2.0.ZU;2-L
Fonte:
ISI
Lingua:
ENG
Soggetto:
MORPHINE-WITHDRAWAL EXCITATION; IN-VITRO; ELECTRICAL-ACTIVITY; MAGNOCELLULAR NEURONS; RECEPTOR ACTIVATION; RAT; INHIBITION; RELEASE; DEPENDENCE; SECRETION;
Keywords:
dependence; hypothalamus; magnocellular neurosecretory cell; morphine; naloxone; mu-opioid receptor; posterior pituitary; supraoptic nucleus; tolerance;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
44
Recensione:
Indirizzi per estratti:
Indirizzo: Russell, JA Univ Edinburgh, Sch Med, Dept Biomed Sci, Edinburgh EH8 9XD, Midlothian, Scotland Univ Edinburgh Edinburgh Midlothian Scotland EH8 9XD Scotland
Citazione:
N. Doi et al., "Effects of the endogenous opioid peptide, endomorphin 1, on supraoptic nucleus oxytocin and vasopressin neurones in vivo and in vitro", BR J PHARM, 132(5), 2001, pp. 1136-1144

Abstract

1 We investigated the actions of the endogenous opioid tetra-peptide endomorphin 1, a selective mu -copioid receptor agonist, on oxytocin and vasopressin cell activity in vivo and in vitro.2 The activity of antidromically-identified supraoptic nucleus cells were recorded from urethane-anaesthetized female rats. The firing rates of both oxytocin and vasopressin cells were reduced by intracerebroventricular endomorphin 1 (5-100 pmol); this inhibition was prevented by intravenous naloxone (5 mg kg(-1)).3 A second group of rats was infused intracerebroventricularly with endomorphin 1 (27 pmol min(-1)) over 5 days. The firing rates of oxytocin and vasopressin cells in endomorphin pre-treated rats were similar to those of endomorphin naive rats, indicating tolerance to the inhibitory effects of endomorphin 1. Intravenous naloxone induced similar modest and transient increases in the firing rate of oxytocin cells in endomorphin 1 pre-treated rats and endomorphin 1 naive rats, indicating that endomorphin 1, unlike the mu -opioid alkaloid agonist, morphine, does not induce mu -opioid dependence in these cells.4 In vitro, whole-cell current clamp recordings were made from supraoptic nucleus cells in superfused coronal hypothalamic slices from young female rats. Endomorphin 1 (100 nM) inhibited the firing rate of oxytocin cells buthad no significant effect on vasopressin cells at up to 10 muM. Inhibitionof oxytocin cells was reversed by naloxone, and remained when synaptic transmission was blocked by superfusion with low Ca2+/Co2+-containing medium.5 Thus, endomorphin 1 directly inhibits oxytocin cells but inhibits vasopressin cells by indirect actions. Chronic endomorphin 1 administration induces mu -opioid tolerance in oxytocin and vasopressin cells but not mu -opioid dependence in oxytocin cells.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/09/20 alle ore 23:42:26