Calcium Influx through Channels Other than Voltage-Dependent Calcium Channels Is Critical to the Pituitary Adenylate Cyclase-Activating Polypeptide-Induced Increase in Excitability in Guinea Pig Cardiac Neurons

摘要

Pituitary adenylate cyclase-activating polypeptide (PACAP) effects on intracellular calcium ([Ca~(2+)] i) and excitability have been stud-ied in adult guinea pig intracardiac neurons. PACAP increased excitability, but did not elicit Ca~(2+) release from intracellular stores. Exposure to a Ca~(2+)-deficient solution did not deplete [Ca~(2+)]i, stores but did eliminate the PACAP-induced increase in excitability. We postulate that Ca~(2+) influx is required for the PACAP-induced increase in excitability.