The Effect of Nerve Stimulation on Catecholamines Taken up in Adrenergic Nerves after Reserpine Pretreatment

Publisher Website
Google Scholar
Abstract
The effect of sympathetic nerve stimulation on the catecholamines (noradrenaline and dopamine) taken up and accumulated after i.v. administration was studied in the adrenergic nerves of rat iris with the fluorescence method and in the salivary glands with biochemical estimations after treatment with reserpine and a monoamine oxidase inhibitor. After administration of noradrenaline (0.1 mg/kg) the stimulation did neither cause a functional response in form of increased pupil diameter or bulb protrusion on the stimulation side, nor any decrease in the amount of noradrenaline accumulated in the examined organs on the same side. However, after administration of dopamine (1.0 mg/kg) there were clearcut functional responses on the stimulated side and a marked decrease of the levels of noradrenaline formed from dopamine. These results imply that exogenous noradrenaline cannot enter the proper sites for release by nerve impulses, 16 hrs after reserpine treatment, but that noradrenaline formed from exogenous dopamine in the doses used and after inhibition of monoamine oxidase can be released by nerve impulses in spite of reserpine pretreatment.