The acute activation of tyrosine hydroxylase from central catecholaminergic neurons, peripheral adrenergic neurons and adrenal medulla following nerve stimulation, stress and administration of drugs known to affect nervous function will be characterized further. Employing monospecific antibody to tyrosine hydroxylase and gel electrophoresis procedures which permit the rapid isolation of tyrosine hydroxylase from tissues, attempts will be made to determine the precise stoichiometry of the phosphorylation of the enzyme and the relation between phosphorylation and enzyme activation. The role of calcium-dependent regulator protein (calmodulin, CDR) and calcium in activation of tyrosine hydroxylase will be assessed. The effects of nerve stimulation, cyclic AMP-dependent protein kinase, phospholipid and anion activation of the enzyme will be compared in order to determine whether the molecular basis for the activation is analogous in all circumstances. Protein kinases and phosphoprotein phosphatases from adrenergic tissues will be purified and characterized and their possible relevance to the activation and deactivation of tyrosine hydroxylase will be determined. The role of cyclic AMP-independent protein kinase in the regulation of tyrosine hydroxylase in central and peripheral adrenergic tissues will be evaluated. The mechanism of the induction of tyrosine hydroxylase in vivo during chronic stress and in PC12 and neuroblastoma cells in culture after exposure to cyclic nucleotides, glucocorticoids or chronic stress depolarizing conditions will be examined further. Ultrastructural localization of tyrosine hydroxylase will be determined by immunocytochemical techniques and the anatomical relationship of tyrosine hydroxylase containing nerve terminals to cholinergic, gabaergic and peptidergic nerve terminals in the brain will be examined. Regulation of catecholamine release consequent to nerve stimulation from brain slices, brain synaptosomes and the isolated vas deferens preparation will be evaluated with particular emphasis on cyclic nucleotides, opioid agonists, alpha adrenoceptor, beta adrenoceptor, dopamine and cholinergic agonists. The relationship between tyrosine hydroxylase activation and dopamine release in amacrine cells of the retina of the rabbit following photic stimulation or electrical stimulation in situ will be determined. The uptake of tyrosine into adrenergic (Text Truncated - Exceeds Capacity)
