[Neuron membrane depolarization under the influence of cyclic-3',5'-adenosine monophosphate and its possible role in...

The separate fourth intracellular microelectrode was used for controlling the conditions of cyclic nucleotide injection in neurons of Helix pomatia. Ionoforetic increase in intracellular cyclic AMP concentration elicits membrane depolarization in many neurons. Phosphodiesterase inhibitors 3-isobutyl-1-methylxantine and SQ-20009 prolong this depolarization and raise its level. In cell F-1 of helix brain sometimes cAMP induces weak hyperpolarization, but this response turns to usual depolarization after 3-isobutyl-1-methylxantine application. It is suggested that cell molecular computer has an analog input, where diffusion of cAMP, cGMP and Ca++ being a modelling process. Adenylate cyclase and guanylate cyclase and ionic channels of membrane are regulated sources. Phosphodiesterases with Ca2+-binding activator proteins are molecular out flowers and protein kinases--detectors that transform the data about the concentrations of cAMP and cGMP into codes for MCC. Protein kinases control over the activity of proteins directly. The depolarization effect on neuron membrane seems to be associated with protein kinase activation or with direct action of cAMP on phospholipase.