Effects of intrathecal administration of neuropeptides on a spinal nociceptive reflex in the rat: VIP, galanin, CGRP, TRH, somatostatin and angiotensin II

The present study examines the effects of intrathecal administration of selected peptides on nociceptive responses in the rat. Each peptide was delivered via a chronically implanted catheter to the L5 vertebral level. In the tail flick test, VIP (0.65-6.5 nmoles) produced a dose-dependent decrease in reaction time (RT) from 1 to 6-16 min after injection; 6.5 nmoles decreased RT to 37% of control value at 1 min after injection. Galanin (0.65-6.5 …