Tuesday, September 16, 2008

Supersensitivity to substance P

The sympathetically denervated parotid gland of the rat develops a supersensitivity to substance P, and VIP injected intravenously. Further, the neuropeptide conttent (VIP and CGRP) of the parasympathetic salivary innervation tends to increase as a a consequence of sympathetic denervation. It has been reported by Harrop and Garrett that little acinar degranulation (or decrease in glandular amylase activity) occurs in the parotid gland in response to food intake in rats if subjected to unilateral sympathetic decentralization before feeding.

Neural Mecahinism of Salivary Gland Secretion By John Raymond Garrett, Jörgen
Published by Karger Publishers, 1999

Parotid Degeneration secretion after sympathectomy

Cell and Tissue Research
Parotid glands of rat have been examined 12, 24 and 48 hours after avulsion of the cervical sympathetic ganglion and compared with the normally innervated left glands. Formaldehyde-induced fluorescence showed a relatively normal complement of adrenergic nerves at 12 hours but most of the nerves had lost their noradrenaline content by 24 hours and no fluorescent nerves were detected at 48 hours.
This loss of granules is considered to be due to sympathetic degeneration secretion caused by the release of noradrenaline from the degenerating adrenergic nerves between 12 and 24 hours after ganglionectomy. This is thought to be the first example of morphological change resulting from degeneration activation to be recorded microscopically.
http://www.springerlink.com/content/n08314p052546477/