cAMP-dependent and cAMP-independent modulation of synaptic transmission in guinea-pig superior cervical ganglion.

RMI 12330A dose-dependently inhibits cAMP accumulation induced by PGE2 in guinea-pig superior cervical ganglion (SCG). Norepinephrine (NE) is unable to modify cAMP concentration in the same preparation. On the other hand, both PGE2 and NE block the firing discharge of guinea-pig SCG neurons elicited by electrical stimulation (1 Hz) of the cervical sympathetic trunk. The effect of PGE2, but not that of NE, is prevented by RMI 12330A, suggesting that NE and PGE2 act through different pathways