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Titolo:
THE ROLE OF AFFERENT INPUTS TO SUPRAOPTIC NUCLEUS OXYTOCIN NEURONS DURING NALOXONE-PRECIPITATED MORPHINE-WITHDRAWAL IN THE RAT
Autore:
MURPHY NP; ONAKA T; BROWN CH; LENG G;
Indirizzi:
BABRAHAM INST,NEUROENDOCRINOL LAB CAMBRIDGE CB2 4AT ENGLAND BABRAHAM INST,NEUROENDOCRINOL LAB CAMBRIDGE CB2 4AT ENGLAND UNIV EDINBURGH,SCH MED,DEPT PHYSIOL EDINBURGH EH8 9AG MIDLOTHIAN SCOTLAND
Titolo Testata:
Neuroscience
fascicolo: 2, volume: 80, anno: 1997,
pagine: 567 - 577
SICI:
0306-4522(1997)80:2<567:TROAIT>2.0.ZU;2-0
Fonte:
ISI
Lingua:
ENG
Soggetto:
DIRECT CATECHOLAMINERGIC PROJECTION; OPIATE-WITHDRAWAL; NORADRENALINE RELEASE; TRACTUS-SOLITARII; ANESTHETIZED RATS; CHOLECYSTOKININ; CLONIDINE; TOLERANCE; HYPOTHALAMUS; PARTURITION;
Keywords:
OPIOID; NORADRENALINE; A2 CELL GROUP; MEDIAN PREOPTIC NUCLEUS; ORGANUM VASCULOSUM OF THE LAMINA TERMINALIS; SUBFORNICAL ORGAN;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
31
Recensione:
Indirizzi per estratti:
Citazione:
N.P. Murphy et al., "THE ROLE OF AFFERENT INPUTS TO SUPRAOPTIC NUCLEUS OXYTOCIN NEURONS DURING NALOXONE-PRECIPITATED MORPHINE-WITHDRAWAL IN THE RAT", Neuroscience, 80(2), 1997, pp. 567-577

Abstract

During prolonged exposure to morphine, oxytocin neurons of the rat supraoptic nucleus develop dependence, shown by hyperexcitation following morphine withdrawal. The present study investigated the role of afferent projections to the supraoptic nucleus in this withdrawal excitation. Rats were made morphine-dependent by continuous intracerebroventricular infusion of morphine at increasing doses (up to 50 mu g/h). On the sixth day, rats were anaesthetized with pentobarbitone and morphinewithdrawal was precipitated by intraperitoneal injection of naloxone (5 mg/kg). Fos-immunoreactivity in the supraoptic nucleus, and also inthe median preoptic nucleus, organum vasculosum of the lamina terminalis and subfornical organ, which project to the supraoptic nucleus, increased following morphine withdrawal. However, retrograde tracing from the supraoptic nucleus showed that, of the neurons in these regions which project to the supraoptic nucleus, only 0.4-7.1% expressed Fos in response to morphine withdrawal. Following morphine withdrawal, Fos-immunoreactivity was present in 39.2% and 19.8% of the tyrosine hydroxylase-immunoreactive neurons of the A1/C1 and A2/C2 cell groups. Of the cells in these regions identified as projecting to the supraoptic nucleus, 11.3% in the region of the A2 cell group and 12.7% in the region of the Al cell group expressed Fos after morphine withdrawal. In a second study, monoamine release was measured in the supraoptic nucleus of urethane-anaesthetized morphine-dependent and -naive rats. Retrodialysis of naloxone (10(-5) M) into the supraoptic nucleus induced a small increase in plasma oxytocin concentration in morphine-dependent rats (13.5+/-4.8 pg/ml increase) but not in naive rats (1.2+/-5.9 pg/ml decrease), with no significant change in monoamine release in either morphine-dependent or -naive rats. Intravenous injection of naloxone (5 mg/kg) 1 h later produced a further significant increase in plasma oxytocin concentration in morphine-dependent rats concomitant with a significant increase in noradrenaline release from the supraoptic nucleus. Thus, morphine-withdrawal excitation of supraoptic oxytocin neurons occurs concurrently with a modestly increased activity of their input from the brainstem, and very little activation in other known inputs. (C) 1997 IBRO. Published by Elsevier Science Ltd.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 21/09/20 alle ore 03:32:01