Fig. 1.
Potentiation of the cyclic adenosine 3′,5′-monophosphate (cAMP)–induced sodium current (INa,cAMP) response amplitude to injected cAMP by nitric oxide (NO) donor and intracellular acidification, and NO-induced depolarization. A: diethylamine/NO (DEA/NO, 1 mM) augmented INa,cAMP response amplitude by 78% relative to control measures in saline alone taken just prior to addition of the NO donor. B: saline containing 30 mM bicarbonate mimicked the effect of NO donor, increasing INa,cAMP amplitude by 41%. Such bicarbonate salines acidify Pleurobranchaea neurons by several tenths of a pH unit (Green and Gillette 1988). Holding potentials were −50 mV. Horizontal bars in records indicate 5 s, 100 nA iontophoretic injections of cAMP.