[Induction of a delayed cyclic AMP-sensitive sodium current in mollusk neurons by G-protein activators]

The experiments have been carried out with isolated Helix pomatia neurons by the method of two-microelectrode voltage clamping. cAMP and the activators of G-proteins, F-, GTP and Gpp (NH)p, were injected via ionophoresis into the neurons using a seven-channel microelectrode. It is found that the G-protein activators induce both input and output currents in the neurons where slow sodium current can be activated by cAMP. The input G-activated and cAMP-activated currents are similar in kinetics, voltage dependence and reverse voltage. The G- and cAMP-responses are not additive. The results obtained allow the conclusion that the G-protein activators can stimulate the slow cAMP-sensitive sodium channels.