title: Phosphorylation of tyrosine hydroxylase in the superior cervical ganglion.
abstract: We studied the phosphorylation of tyrosine hydroxylase in the superior cervical ganglion of the rat. Ganglia were preincubated with [32P]Pi and were then incubated in non-radioactive medium containing a variety of agents that are known to activate tyrosine hydroxylase in this tissue. Tyrosine hydroxylase was isolated from homogenates of the ganglia by immunoprecipitation followed by polyacrylamide gel electrophoresis. 32P-labelled tyrosine hydroxylase was visualized by radioautography, and the incorporation of 32P into the enzyme was quantitated by densitometry of the autoradiograms. Veratridine produced a concentration-dependent increase in the incorporation of 32P into tyrosine hydroxylase, with 50 microM veratridine producing a 5-fold increase in 32P incorporation. The nicotinic agonist, dimethylphenylpiperazinium (100 microM), caused a 7-fold increase in the phosphorylation of tyrosine hydroxylase. The effect of dimethylphenylpiperazinium was maximal within 1 min and decreased upon continued exposure of the ganglia to this agent. The actions of dimethylphenylpiperazinium and of veratridine were dependent on extracellular Ca2+. Muscarine, 8-Br-cAMP, forskolin, vasoactive intestinal peptide, isoproterenol, deoxycholate and phospholipase C also stimulated the incorporation of 32P into tyrosine hydroxylase. These data support the hypothesis that phosphorylation plays a role in activation of tyrosine hydroxylase produced by all of these agents.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology; D000242:Cyclic AMP / Q000502:physiology; D004246:Dimethylphenylpiperazinium Iodide / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D005728:Ganglia, Sympathetic / Q000201:enzymology*; D007163:Immunosorbent Techniques; D007700:Kinetics; D008297:Male; D010710:Phosphates / Q000378:metabolism; D010761:Phosphorus Radioisotopes; D010766:Phosphorylation; D051381:Rats; D011919:Rats, Inbred Strains; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*; D014701:Veratridine / Q000494:pharmacology
chemical_list: D010710:Phosphates; D010761:Phosphorus Radioisotopes; D004246:Dimethylphenylpiperazinium Iodide; D014701:Veratridine; D000242:Cyclic AMP; D014446:Tyrosine 3-Monooxygenase; D002118:Calcium