[The intracellular signal systems of the smooth muscles in the gastrointestinal tract].

The authors summarize the data available in the literature and their own findings of the gastrointestinal smooth muscle messenger systems. They describe the mechanisms that regulate the cytoplasmic cell concentrations of calcium, its role as a second messenger in the smooth muscle cells. Special attention is paid to calmodulin. Data are given as to the contribution of inositol triphospate and diacylglycerol to the release of intracellular calcium and to the manifestation of its effects. The authors also outline the cellular adenylate cyclase system and show its role in smooth muscle relaxation that occurs with the activation of the cAMP-dependent signal pathway.