[Study of the metabolic synapse. II. Comparison of the effects of cyclic 3',5'-AMP and 3',5'-GMP].

Intracellular microiontoforetic injections of cyclic 3',5'-AMP and cyclic 3',5'-GMP elicit different responses in the same neuron. Drugs were injected by current of 1--10 nA using 3-barrel micropipettes. Unlike cyclic 3',5'-AMP arising the depolarization of the neuron, cyclic 3',5'-GMP usually hyperpolarizes it. An inhibitor of phosphodiesterases, papaverine, increases and prolongates effects of cyclic 3',5'-AMP and cyclic 3',5'-GMP, but in latter case the action of this drug seems to be less.