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