Central Imidazoline- and α2-Receptors Involved in the Cardiovascular Actions of Centrally Acting Antihypertensive Agentsa

摘要: There has been a continuing and yet unresolved debate concerning the existence contribution of imidazoline receptors to antihypertensive actions clonidine-like agents. Studies from our laboratory have examined importance alpha 2-adrenoceptors in mechanism action centrally acting drugs. We used conscious rabbits specific 2-adrenoceptor antagonists show that second-generation agents rilmenidine moxonidine act preferentially through but are important for hypotension produced by clonidine alpha-methyldopa. Using microinjections into rostral ventrolateral medulla (RVLM) anesthetized we confirmed generally held view this is major site sympathoinhibitory However, also found present nucleus appear be activated as consequence receptor activation. In recent studies using noradrenergic neurotoxin microinjected RVLM treatment selectively blocked did not affect level imidazole proteins, suggesting I1-imidazoline may located presynaptic terminal. By contrast, acts directly on perhaps cell bodies nucleus. conclusion, suggest within