Abstract

The vasopressor effects of several cycloalkane carbonylcholines have been examined in the dog. The order of activity was as follows: cyclopropane carbonylcholine > cyclobutane carbonylcholine > cyclopentane carbonylcholine > cyclohexane carbonylcholine. The pressor activity of these substances was compared with that of the corresponding saturated and unsaturated alkyl acid esters of choline. It would appear from the analysis that the cyclopropyl and cyclobutyl ring systems are equivalent to a double bond in the β,β position in the acyl side chain of aliphatic acid esters of choline. Physical evidence in favor of this view is discussed. These findings lend further support to the thesis that the formal negative charge density on the carbonyl oxygen is one important factor determining the intensity of the pressor activity of cholinesters.