[Comparative-biochemical study of phosphoinositides as functionally active components of excitable nerve fiber membranes].

The effect of acetylcholine (ACh) and cyclic 3',5'-adenosine monophosphate (cAMP) on phosphoinositide (PI) metabolism and associated changes of the permeability of the nervous fibers in the crustaceans Carcinum maenas and Eriphia spinifrons, as well as in the frog Rana temporaria, has been investigated. It was shown that ACh induces a significant decrease in the content of triphosphoinositides (TPI) in the nervous fibers of the crabs and increases their potassium permeability, which in its turn results in depolarization of the fibers. ACh did not affect frog nervous fibers.