Release of catecholamines and [Met5]enkephalin immunoreactive material from perfused bovine adrenal glands

Retrogradely perfused bovine adrenal glands were stimulated by acetylcholine (ACh) and 1,1-dimethyl-4-phenyl-piperazinium (DMPP), with or without hexamethonium. Stimulation by either agent resulted in an increased release of both [Met5]enkephalin immunoreactive material (ME-IRM) and catecholamines as measured by radioimmunoassay and high performance liquid chromatography with electrochemical detection, respectively. ACh (5 X 10(-5) M) and DMPP (5 X 10(-5) M) stimulated the release of norepinephrine greater than the release of epinephrine. The action of these agents was antagonized by hexamethonium (5 X 10(-4) M). DMPP produced the same percentage increase in the release of ME-IRM and norepinephrine but produced a greater percentage increase in the release of ME-IRM compared to the release of epinephrine. There was no apparent correlation between the percentage increase in the release of ME-IRM and either norepinephrine or epinephrine after ACh.