The objective of the proposed research is to elucidate the role of adenosine 3',5'-monophosphate (cyclic AAP), guanosine 3',5'-monophosphate (cyclic GMP), and membrane protein phosphorylation in the process of synaptic transmission in the peripheral nervous system. For the purpose o this study, the mammalian superior cervical ganglion will be used as a model containing nerve cell bodes and synapses. The effect of physiological activity, induced by electrical stimulation of the peganglionic nerve trunk, will be studied on the leve of cyclic GMP in the ganglion. Any change in cyclic GMP concentration, associated with synaptic tranmission, will be anaayzed using various pharmacological agents, including cholinergic agonists, norepinephrine, and dopamine, as well as cholinergic, adrenergic and dopaminergic blocking drugs. The effect of these various experimental manipulations on the levels of cyclic GMP in the ganglion will be compared with the effects on cyclic AMP in the same tissue. The possibility of an antagonistic interaction between the acetylcholine-cyclic GMP system and the dopamine-cyclic AMP system in the ganglion will be studied. The dopamine-sensitive adenylate cyclase of the ganglion will be characterized, and its properties compared with the properties of the dopamine-sensitive adenylate cyclase of the caudate nucleus of the mammalian central nervous system. The effect of preganglionic stimulation and of various pharmacological agents will be studied on the level of phosphorylation of membrane proteins. A study will be carried out, using electrophysiological techniqes, to elucidate the ionic basis of the hyperpolarization of the postganglionic neurons induced by dopamine and by cyclic AMP, and of the depolarization of the same cells, induced by muscarinic agonists and by cyclic GMP.