Inhibition by halothane of release of norepinephrine, but not of dopamine-beta-hydroxylase, from guinea-pig vas deferens.

Halothane strikingly decreases spontaneous and electrically stimulated release of norepinephrine from the isolated guinea pig hypogastric nerve--vas deferens preparation. This depression of adrenergic discharge appears to be a direct action on the sympathetic nerve endings and may in part account for the cardiovascular depression seen during halothane administration. Although halothane depressed stimulation-induced release of norepinephrine, it did not proportionately diminish release of dopamine-beta-hydroxylase. Possible mechanisms of the dissociation between catecholamine and enzyme release are discussed.