Evidence for the co-storage and co-release of neuropeptide Y and noradrenaline from large dense cored vesicles in sympathetic nerves of the bovine vas deferens.

The subcellular localization and the secretion of neuropeptide Y were studied in sympathetic nerve endings of bovine vas deferens. Immunostaining revealed a parallel distribution for neuropeptide Y and dopamine-beta-hydroxylase immunoreactivity in the network of varicose nerve fibers in the smooth muscle layers of the vas deferens. Following differential centrifugation and sucrose density gradient centrifugation, neuropeptide Y was found to coincide with noradrenaline in the more dense region of the gradient, where the large dense cored vesicles are found.

Facilitation of the release of noradrenaline and neuropeptide Y by the alpha 2-adrenoceptor blocking agents idazoxan and hydergine in the dog spleen.

The release of noradrenaline (NA) together with its possible cotransmitter neuropeptide Y (NPY) was investigated in the perfused dog spleen. The splenic nerve was stimulated electrically at high frequency with bursts, which evoked a simultaneous release of both substances. Infusion of the alpha 2-adrenergic blocking agents idazoxan or hydergine enhanced the amount of NA and NPY in the venous effluent.