Effects of dibutyryl cyclic adenosine 3',5'-monophosphate and theophylline on the bullfrog sympathetic ganglion cells.

1 Effects of dibutyryl cyclic adenosine 3',5'-monophosphate (dibutyryl cyclic AMP) and theophylline on bullfrog sympathetic ganglion cells were examined in order to test the hypothesis that cyclic AMP is essential for the generation of slow inhibitory postsynaptic potentials (i.p.s.ps) in these cells. 2 In the absence or presence of theophylline, dibutyryl cyclic AMP did not hyperpolarize but rather tended to depolarize ganglia that were hyperpolarized by adrenaline. 3 Theophylline augmented neither the P-potential (slow i.p.s.p.) nor adrenaline-induced hyperpolarization. 4 Thus, cyclic AMP does not seem to be essential for the generation of the slow i.p.s.p., at least in amphibian sympathetic ganglion cells.