Role of Acetylcholine in Regulation of Interaction between Axon and Schwann Cell during Rhythmic Excitation of Nerve Fibers

G. V. Maximov^1*, V. V. Revin², I. P. Grunyushkin², and O. R. Kols¹

¹School of Biology, Lomonosov Moscow State University, Moscow, 119899 Russia; fax: (7-095) 939-1115; E-mail: maxim@biophys.msu.ru

²School of Biology, Ogarev Mordov State University, ul. Bol'shevistskaya 68, Saransk, 430000 Russia; fax: (834) 2-322-523

^* To whom correspondence should be addressed.

Received December 24, 1998; Revision received June 2, 1999

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Axon excitation increases the number of acetylcholine receptors (ACR) of the Schwann cell (SC) depending on the frequency of rhythmic excitation (RE) and on intercellular concentrations of K⁺, Ca²⁺, and acetylcholine. During RE, activity of axonal acetylcholine esterase is decreased, thus providing for high intercellular acetylcholine concentration. Increased intercellular concentration of acetylcholine activates phosphoinositide-specific phospholipase C (PIPLC) of the myelin nerve fiber. During RE, K⁺ depolarization and acetylcholine exocytosis can activate Ca²⁺ entry via Ca²⁺ channels, thus inducing SC ACR phosphorylation mediated by PIPLC stimulation.

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KEY WORDS: acetylcholine, Ca²⁺, acetylcholine receptor, acetylcholine esterase, phosphoinositide-specific phospholipase C, Schwann cell, axon, astrocyte

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