Complementary action of substance P and vasoactive intestinal peptide on the rat parotid secretion

Publisher Website
Google Scholar
Abstract
Augmentation of the rat parotid salivary secretion to intravenous injections of substance P (SP) occurred when SP was combined with vasoactive intestinal peptide (VIP), or stimulation of the auriculotemporal nerve in the presence of atropine and the adrenergic blockers, dihydroergotamine and propranolol. The largest increase was obtained when SP (0.5 μg kg‐1) was used together with subthreshold doses of VIP (84% at 0.05 μg kg‐1 and 105% at 0.5 μg kg‐1) and low frequency stimulation (92% at 2 Hz and 97% at 5 Hz), which did not produce any salivary secretion by itself. There was no facilitated secretion when VIP and nerve stimulation were combined. Amylase output was much larger (250–500%) when SP was combined with nerve stimulation (0.5‐5 Hz) or VIP (0.005‐5 μg kg‐1) than when SP was used alone. Similar results were obtained in rats where the auriculo‐temporal nerve was stimulated during the early phase (24–90 h) of Wallerian degeneration, when the nerve‐induced responses were seemingly completely blocked. Our results are consistent with the hypothesis that both VIP and SP contribute to the atropine‐resistant parotid secretion, and that they have a complementary role in the rat parotid exocrine function.

This publication has 21 references indexed in Scilit: