Electrical Stimulation Increases Phosphorylation of Tyrosine Hydroxylase in Superior Cervical Ganglion of Rat

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 81; no. 22; pp. 7243 - 7247
• Main Authors: Cahill, Anne L., Perlman, Robert L.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 01.11.1984; National Acad Sciences
• Subjects: Animals; Atropine; Catecholamines; Electric Stimulation; Electrical stimulation; Electrodes; Electrophoresis; Ganglia; Ganglia, Sympathetic - enzymology; Gels; Immunoprecipitation; Isoelectric Point; Male; Molecular Weight; Nerves; Phosphorylation; Rats; Rats, Inbred Strains; Tyrosine 3-Monooxygenase - metabolism
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.81.22.7243

Electrical stimulation of the superior cervical ganglion of the rat increased the phosphorylation of tyrosine hydroxylase (tyrosine 3-monooxygenase, EC 1.14.16.2) in this tissue. Ganglia were incubated with [32P]Pifor 90 min and were then electrically stimulated via the preganglionic nerve. Tyrosine hydroxylase was isolated from homogenates of the ganglia by immunoprecipitation followed by polyacrylamide gel electrophoresis.32P-labeled tyrosine hydroxylase was visualized by radioautography, and the incorporation of32P into the enzyme was quantitated by densitometry of the radioautograms. Stimulation of ganglia at 20 Hz for 5 min increased the incorporation of32P into tyrosine hydroxylase to a level 5-fold that found in unstimulated control ganglia. The increase in phosphorylation of tyrosine hydroxylase was dependent on the duration and frequency of stimulation. Preganglionic stimulation did not increase the phosphorylation of tyrosine hydroxylase in a medium that contained low Ca2+and high Mg2+. Increases in phosphorylation were reversible; within 30 min after the cessation of stimulation, the incorporation of32P into tyrosine hydroxylase decreased to the level found in unstimulated ganglia. The nicotinic antagonist hexamethonium reduced the increase in32P incorporation into tyrosine hydroxylase by about 50%, while the muscarinic antagonist atropine had no effect. Thus, preganglionic stimulation appeared to increase the phosphorylation of tyrosine hydroxylase in part by a nicotinic mechanism and in part by a noncholinergic mechanism. Antidromic stimulation of ganglia also increased the phosphorylation of tyrosine hydroxylase. Two-dimensional gel electrophoresis revealed that electrical stimulation also increased the incorporation of32P into at least six other phosphoproteins in the ganglion.