[The effect of cAMP on the calcium currents of mollusk neurons possessing different sensitivities of their calcium conductance to serotonin action].
The action of cAMP (100 microM) and serotonin (5-HT, 1-10 microM) on the calcium current (Ica) in intracellularly perfused Helix pomatia neurons was studied with voltage clamp method. Three types of 5-HT-induced changes in the calcium current were observed in different cells: reversible blockade, increase and no changes in the current amplitude. Intracellular introduction of exogenous cAMP (100 microM) affected Ica only in cells with the stimulatory effect of 5-HT; cAMP-induced increase in the current amplitude was not additive to that elicited by 5-HT while both of these effects were similarly potentiated by cyclic nucleotide-phosphodiesterase inhibitor. The data presented show that the stimulatory action of 5-HT on the potential-activated calcium current is mediated by an increase in intracellular cAMP. Existence of two types of calcium channels differing in their dependence on cAMP metabolism is suggested in the snail neurons. The presence of the cAMP-dependent calcium channels seems to correlate with the existence of the definite type of 5-HT receptors in the cell membrane. A new approach to the investigation of isolated neurons is suggested: their functional identification.
Kostiuk
P G
PG
Luk'ianets
E A
EA
Doroshenko
P A
PA
D000818:Animals; D015220:Calcium Channels / Q000187:drug effects* / Q000502:physiology; D000242:Cyclic AMP / Q000494:pharmacology*; D004347:Drug Interactions; D006372:Helix, Snails / Q000187:drug effects* / Q000502:physiology; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D010477:Perfusion / Q000379:methods; D012701:Serotonin / Q000494:pharmacology*
D015220:Calcium Channels; D012701:Serotonin; D000242:Cyclic AMP
Vliianie tsAMF na kal'tsievye toki neĭronov molliuskov, obladaiushchikh razlichnoĭ chuvstvitel'nost'iu ikh kal'tsievoĭ provodimosti k deĭstviiu serotonina.