Impairment of sympathetic nerve responses by dopa, dopamine and their α-methyl analogues

Abstract

Abstract Dopa and dopamine reduced the response of the nictitating membrane to postganglionic sympathetic nerve stimulation in cats pretreated with the monoamine oxidase inhibitor pargyline. A similar reduction could be obtained with α-methyldopa and α-methyldopamine in untreated cats. The sensitivity of the membrane to injected noradrenaline, α-methylnoradrenaline or adrenaline was not reduced. The possible mechanism of the anti-hypertensive action of monoamine oxidase inhibitors and α-methyldopa is discussed in the light of these findings.