The purpose of the proposed work is to elucidate the specific structure, function and relationship between sturcture and function of norepinephrine-containing vesicles in peripheral sympathetic nerves, in particular, vesicles of the large dense core type, and their possible relationship with the smaller vesicles, both of which are found in all noradrenergic terminals. The study includes determination of the chemical composition of purified large dense core vesicles; release of vesicle contents by exocytosis; origin of dopamine beta-hydroxylase in the circulation; and the effects of physiological stress, disease and pharmacological agonists and antagonists to modify the release.