[Modulation of calcium conductance of the somatic membrane of sensory neurons of the rat upon activation of the adenylate cyclase system].

Intracellular second messenger system modifies the function of the voltage-dependent calcium conductance. Changes in the latter were investigated under the influence of cholera toxin (potent activator of adenylate cyclase). It was found that lower concentrations of toxin led to an increase of calcium conductance, while higher concentrations suppressed it. The bell-shaped dependence between calcium conductance and cholera toxin concentration indicates that cAMP-dependent protein kinase is connected with the intracellular cAMP concentration in the same way, i.e. a rise of the cAMP concentration from the basal level first activates protein kinase and then results in the inhibitory effect due to the cAMP excess.