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Titolo:
ANTAGONIST PRECIPITATED CLONIDINE WITHDRAWAL IN RAT - EFFECTS ON LOCUS-COERULEUS NEURONS, SYMPATHETIC-NERVES AND CARDIOVASCULAR PARAMETERS
Autore:
GRUBB MC; STORNETTA RL; PENCE R; BAERTSCHI AJ; GUYENET PG;
Indirizzi:
UNIV VIRGINIA,HLTH SCI CTR,DEPT PHARMACOL,BOX 448,1300 JEFFERSON PK AVE CHARLOTTESVILLE VA 22908 UNIV VIRGINIA,HLTH SCI CTR,DEPT PHARMACOL CHARLOTTESVILLE VA 22908 UNIV VIRGINIA,DEPT MOL PHYSIOL & BIOL PHYS CHARLOTTESVILLE VA 22908 OREGON HLTH SCI UNIV,DEPT BEHAV NEUROSCI PORTLAND OR 97201
Titolo Testata:
Journal of the autonomic nervous system
fascicolo: 2-3, volume: 71, anno: 1998,
pagine: 85 - 95
SICI:
0165-1838(1998)71:2-3<85:APCWIR>2.0.ZU;2-2
Fonte:
ISI
Lingua:
ENG
Soggetto:
CENTRAL-NERVOUS-SYSTEM; NORADRENERGIC NEURONS; MORPHINE-WITHDRAWAL; RECEPTOR SUBTYPE; BINDING-SITES; SUBSTANCE-P; ALPHA-2-ADRENOCEPTORS; ATIPAMEZOLE; CATECHOLAMINES; HYPERTENSION;
Keywords:
ALPHA(2)-ADRENERGIC RECEPTORS; TOLERANCE AND DEPENDENCE; CLONIDINE; ANTAGONIST PRECIPITATED WITHDRAWAL; NEURAL CONTROL OF CIRCULATION; LOCUS COERULEUS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
58
Recensione:
Indirizzi per estratti:
Citazione:
M.C. Grubb et al., "ANTAGONIST PRECIPITATED CLONIDINE WITHDRAWAL IN RAT - EFFECTS ON LOCUS-COERULEUS NEURONS, SYMPATHETIC-NERVES AND CARDIOVASCULAR PARAMETERS", Journal of the autonomic nervous system, 71(2-3), 1998, pp. 85-95

Abstract

The goal of the present study was to examine the effect of clonidine withdrawal on the neural control of blood pressure. Rats were treated for 7-13 days with clonidine via osmotic minipumps (200 mu g kg(-1) day(-1), s.c.). Controls received saline or were sham operated. Withdrawal was precipitated by the alpha(2)-adrenergic receptor (alpha(2)-AR) antagonist atipamezole. Most experiments were done under halothane anesthesia. Chronic treatment with clonidine did not change mean arterialpressure (MAP) or heart rate (HR) but raised femoral artery resistance and the activity of locus coeruleus neurons slightly. Atipamezole given to rats treated chronically with clonidine produced the following effects: no change in MAP, severe tachycardia, sustained increase in splanchnic sympathetic nerve discharge (SND; +75 +/- 13%), transient increase in lumbar SND (+23 +/- 7%), ON-OFF activity pattern in the locus coeruleus (LC). The ON phase of LC activity was synchronized with upswings of SND and with small changes in MAP. A second alpha(2)-AR antagonist, methoxyidazoxan, produced effects identical to those of atipamezole. Atipamezole given to control rats produced no effect on MAP, KR, SND or LC activity. Atipamezole reversed the hypotension, sympathoinhibition and bradycardia produced by acute administration of clonidine. In awake rats treated chronically with clonidine, atipamezole did not change MAP but produced arterial pressure lability and tachycardia. In conclusion, under anesthesia, selective alpha(2)-AR antagonists elicit a clonidine withdrawal syndrome that displays autonomic characteristics reminiscent of the spontaneous withdrawal syndrome found in awake rats. The most prominent features of this syndrome are tachycardia, sympathoactivation, lack of hypertension and an oscillating activity pattern of brainstem neurons leading to abrupt changes in SND and in MAP. (C) 1998 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 09/04/20 alle ore 20:03:41