Recovery of alpha-adrenoreceptor mediated responses and binding site number after intravenous benextramine in the rabbit.
J Auton Pharmacol
; 5(1): 13-7, 1985 Mar.
Article
en En
| MEDLINE
| ID: mdl-2859290
The densities of [3H]-prazosin and [3H]-clonidine binding sites were determined in spleen and brain membrane preparations from rabbits treated 1 to 48 h previously with benextramine (5 mg/kg). In other rabbits pressor responses to phenylephrine and BHT 920 were examined 1 to 72 h after benextramine administration. After benextramine there was a reduction in the density of both [3H] prazosin and [3H] clonidine binding sites in spleen and a non-parallel shift in pressor dose response curves to selective alpha 1- and alpha 2-adrenoreceptor agonists. Recovery of in vivo responses and binding site densities were relatively slow. No reduction in the maximum density of either [3H] prazosin or [3H] clonidine binding sites in brain was found after intravenous administration of benextramine. It is concluded that after intravenous administration benextramine binds irreversibly to peripheral alpha 1- and alpha 2-adrenoreceptors in the rabbit but fails to cross the blood brain barrier in appreciable quantities and bind to central alpha-adrenoreceptors. Recovery of in vivo responses was more rapid than that previously observed after alpha-adrenoreceptor blockade with phenoxybenzamine. The longer time course of recovery after phenoxybenzamine may be a result of redistribution of this lipophilic drug from fat.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Receptores Adrenérgicos alfa
/
Antagonistas Adrenérgicos alfa
/
Cistamina
Límite:
Animals
Idioma:
En
Revista:
J Auton Pharmacol
Año:
1985
Tipo del documento:
Article
Pais de publicación:
Reino Unido