Desensitization and down-regulation of brain alpha 2-adrenoceptors by centrally acting antihypertensive drugs.
Br J Clin Pharmacol
; 30 Suppl 1: 131S-134S, 1990.
Article
em En
| MEDLINE
| ID: mdl-2176517
ABSTRACT
Rabbits were treated with intravenous clonidine (8 mumol kg-1 day-1), guanabenz (20 mumol kg-1 day-1), rilmenidine (80 mumol kg-1 day-1) or vehicle via osmotic minipumps. After 6 days treatment mean arterial pressure (MAP), pressor responses to intravenous alpha-methyl noradrenaline and depressor responses to intracisternal clonidine were studied, and [3H]-yohimbine binding to forebrain and hindbrain examined in vitro. Clonidine, guanabenz and rilmenidine had similar effects on MAP and caused a similar attenuation of the depressor response to intracisternal clonidine, but only guanabenz attenuated pressor responses to intravenous alpha-methyl noradrenaline. Rilmenidine had no effect on [3H]-yohimbine binding to brain membranes. Clonidine treatment decreased binding in hindbrain while guanabenz treatment decreased binding in both fore- and hindbrain. Thus, the depressor effects of chronic treatment did not correlate with the effects on [3H]-yohimbine binding sites in rabbit brain suggesting that the blood pressure lowering effects of many centrally acting antihypertensive drugs are not necessarily dependent on binding to the alpha 2-adrenoceptor site labelled by [3H]-yohimbine.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Encéfalo
/
Regulação para Baixo
/
Receptores Adrenérgicos alfa
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Anti-Hipertensivos
Limite:
Animals
Idioma:
En
Revista:
Br J Clin Pharmacol
Ano de publicação:
1990
Tipo de documento:
Article