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Titolo:
MEDIATION OF THE HYPOTENSIVE ACTION OF SYSTEMIC CLONIDINE IN THE RAT BY ALPHA(2)-ADRENOCEPTORS
Autore:
HIEBLE JP; KOLPAK DC;
Indirizzi:
SMITHKLINE BEECHAM PHARMACEUT,DEPT PHARMACOL KING OF PRUSSIA PA 19406
Titolo Testata:
British Journal of Pharmacology
fascicolo: 4, volume: 110, anno: 1993,
pagine: 1635 - 1639
SICI:
0007-1188(1993)110:4<1635:MOTHAO>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
IMIDAZOLINE-PREFERRING RECEPTORS; BINDING-SITES; BRAIN-STEM; INVITRO CHARACTERIZATION; VENTROLATERAL MEDULLA; CEREBRAL-CORTEX; H-3 IDAZOXAN; RILMENIDINE; SELECTIVITY; DRUGS;
Keywords:
ALPHA(2)-ADRENOCEPTORS; IMIDAZOLINE RECEPTORS; IDAZOXAN; GUANABENZ; SK-AND-F 86466; CENTRALLY ACTING ANTIHYPERTENSIVES; ROSTRAL VENTROLATERAL MEDULLA;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
35
Recensione:
Indirizzi per estratti:
Citazione:
J.P. Hieble e D.C. Kolpak, "MEDIATION OF THE HYPOTENSIVE ACTION OF SYSTEMIC CLONIDINE IN THE RAT BY ALPHA(2)-ADRENOCEPTORS", British Journal of Pharmacology, 110(4), 1993, pp. 1635-1639

Abstract

1 During the past few years it has been shown that the sympatholytic effect resulting from localized microinjection of clonidine and other imidazolines into the rostral ventrolateral medulla (RVL) results fromactivation of 'imidazoline' receptors (I1 receptors) rather than froman alpha2-adrenoceptor-mediated effect. 2 The relative contributions of these two receptor systems to the hypotensive action of systemically administered clonidine have not been studied. Clonidine has afffinity for both I1, and alpha2-adrenoceptors; guanabenz represents a usefulpharmacological tool, since it activates only the alpha2-adrenoceptor. 3 Antagonists acting at both I1 and alpha2-adrenoceptors (idazoxan) and at only alpha2-adrenoceptors (SK&F 86466; -chloro-3-methyl-2,3,4,5-tetrahydro-3-benzazepine) are available. Idazoxan (1 mg kg-1, i.v.) and SK&F 86466 (3 mg kg-1, i.v.) produced an equivalent degree of blockade of the pressor response to guanabenz or clonidine in the pithed rat, a response mediated by the alpha2-adrenoceptor. 4 Guanabenz (30 mugkg-1, i.v.) and clonidine (10 mug kg-1, i.v.) lowered blood pressure in the chloralose-anaesthetized spontaneously hypertensive rat by 48 +/- 4.6 mmHg and 44 +/- 5.4 mmHg, respectively; this response, for either agonist, was blocked by both idazoxan and SK&F 86466. 5 These data show that the hypotensive effect of intravenously administered clonidine results from activation of central alpha2-adrenoceptors, with no significant contribution from an I1-mediated effect. Thus clonidine can lower blood pressure by different receptor mechanisms, dependent on the route of administration.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 26/09/20 alle ore 05:45:54