Synthesis and peripheral cardiovascular action of cis- and trans-2-(3,4-dimethoxybenzyl)cyclopentylamine hydrochlorides.

The hydrochlorides of cis- and trans-2-(3,4-dimethoxybenzyl)cyclopentylamine have been synthesized. They are transient hypotensive agents with early and delayed depressor effects and antagonists of dopamine-induced vasodepression. In the atropinized and phenoxybenzamine-treated dog, the threshold dose for hypotension was 3-5 mumol/kg. The early depressor phases were attenuated variably by different types of antagonists, suggesting a nonspecific interaction with blood pressure regulation mechanisms. Cimetidine blocked the delayed depressor phases, consistent with endogenous histamine release. The cis amine hydrochloride was three to four times more potent than its trans isomer as a peripheral dopamine blocking agent. Cimetidine but not diphenhydramine interfered with this effect.