Fig. 1.

Bath application of nanomolar concentrations of pituitary adenylate cyclase-activating polyeptide (PACAP) increases neuronal excitability. A: responses to depolarizing current pulses (1 s) of increasing intensities (0.1–0.4 nA) in the same cell before (control) and 5 min after application of 10 nM PACAP (PACAP). Multiple action potentials were generated during exposure to PACAP. B: percentage of neurons firing ≥5 action potentials (APs) in response to suprathreshold depolarizing current pulses in control preparations and ganglia preparations exposed to 1, 10, or 50 nM PACAP for up to 120 min. Total number of cells exposed to peptide at each concentration is given in parentheses. C: number of action potentials produced by a 0.3-nA current pulse in different cells impaled at different times during 120-min exposure to 1, 10, or 50 nM PACAP.