Effects of 8-Br-cAMP on resting membrane potential (RMP), unitary potentials and nitrergic biphasic inhibitory junction potentials (IJPs) in the presence of apamin. Panel A demonstrates that 8-Br-cAMP (1 mM, 10 min) hyperpolarized RMP by about 7 mV over control. (B, panels a–c) Nitrergic IJPs from panel A, on an expanded time scale, in control, 5 min and 10 min after application of 8-Br-cAMP. (B, panel d) Superimposed nitrergic biphasic IJPs in comparison. 8-Br-cAMP increased the amplitude of the biphasic IJPs.