Properties of cAMP-induced transmembrane current in mollusc neurons.
The effects of different substances affecting some or other chains of cAMP metabolism on the properties of transmembrane current induced by cAMP injection have been studied in Helix pomatia neurons. It was found that preinjection of papaverine or adenosine triphosphate from a microelectrode into the neuron increases the cAMP-current amplitude. Injection of dibutyryl-cAMP does not induce transmembrane current by itself but results in a noticeable reversible inhibition of cAMP-current. Extracellular administration of trifluoperazine produces either an increase or a decrease of the cAMP-current amplitude in different cells but in both cases its removal restores the initial amplitude of cAMP-current. Furosemide has no appreciable effect on cAMP-current. An increase in intracellular Ca2+ concentration (by iontophoretic injection through a microelectrode, generation of a burst of action potentials, application of dinitrophenol, tetraphenylphosphonium or caffeine) considerably enhances the amplitude of cAMP-current. The amplitude of cAMP-current remains increased for many minutes after return of the intracellular Ca2+ level to its initial value. A possible physiological role of the observed effect is discussed.
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology*; D006152:Cyclic GMP / Q000494:pharmacology; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D006372:Helix, Snails; D007473:Ion Channels / Q000187:drug effects*; D009431:Neural Conduction / Q000187:drug effects*; D012964:Sodium / Q000378:metabolism*; D014268:Trifluoperazine / Q000494:pharmacology
D007473:Ion Channels; D014268:Trifluoperazine; D006165:Guanylyl Imidodiphosphate; D003994:Bucladesine; D000255:Adenosine Triphosphate; D012964:Sodium; D000242:Cyclic AMP; D006152:Cyclic GMP; D002118:Calcium