PATCH-CLAMP RECORDING OF CAMP-INDUCED MEMBRANE CURRENT NOISE IN HELIX-POMATIA NEURONS

Membrane current noise evoked by intracellular cAMP injection was stud ied in isolated Helix pomatia neurons with the patch-clamp technique. Fluctuation analysis was used to estimate the elementary current ampli tude (i) and the single channel conductance. It was found that i decre ased lineary with cell depolarization and the extrapolated reversal po tential was almost-equal-to -1 2 mV The calculated single-channel cond uctance was 0.9 +/-0.14 pS, a value quite different from those obtaine d for cAMP-activated channels in Pleurobranchaea neurons.