Vasoactive intestinal polypeptide elicits a discharge in chronically decentralized sympathetic ganglia

Vasoactive intestinal polypeptide (VIP, 5-50 micrograms) injected intraarterially to the chronically decentralized cat superior cervical ganglion elicited a prolonged (2-5 min) postganglionic discharge which was resistant to cholinergic blocking agents but was blocked by [Leu5]enkephalin and GABA (10-200 micrograms i.a.). VIP did not elicit a discharge in acutely decentralized ganglia. These findings indicate that VIP has direct excitatory effects on ganglion cells and that these excitatory effects are enhanced following degeneration of the preganglionic nerve terminals.