PACAP occurs in sensory nerve fibers and participates in ocular inflammation in the rabbit.

PACAP is a sensory neuropeptide; it occurs together with CGRP in a population of C fibers in the rabbit eye. PACAP is likely to be involved in the inflammatory response in as much as PACAP-induced responses mimic the symptoms of inflammation and because the concentration of PACAP-LI in the aqueous humor increased greatly in response to noxious stimuli. The observation that capsaicin releases both PACAP and CGRP from the iris and ciliary body supports the view that PACAP is present in C fibers in the rabbit eye.