AJP - Gastrointestinal and Liver Physiology, Vol 264, Issue 5 935-G938, Copyright © 1993 by American Physiological Society
Mitogenic activity of rat salivary glands after electrical stimulation of parasympathetic nerves
C. A. Schneyer, M. G. Humphreys-Beher, H. D. Hall and D. Jirakulsomchok
Laboratory Exocrine Physiology, University of Alabama, Birmingham 35294.
Electrical stimulation of the parasympathetic innervation to parotid or
submandibular gland for 30 or 60 min resulted in increased [3H]thymidine
uptake of both glands when measurements were made 18 h later. With 30 min
of stimulation, the mean increase in parotid was 30% compared with
unstimulated mates, and after 60 min of stimulation, the increase was 76%.
Stimulation for 30 min with the adrenergic antagonists propranolol and
phenoxybenzamine present showed an increase in [3H]thymidine of 76%.
Stimulation of the chorda tympani for 30 min resulted in a mean increase of
59% in thymidine uptake of the sympathectomized submandibular gland
compared with the unstimulated sympathectomized mate.
beta-1,4-Galactosyltransferase activity of both stimulated parotid and
submandibular glands also showed an increase of 71%. On the basis of the
composition of the saliva in the oral cavity, we confirmed the identity of
the stimulated nerve to parotid gland as the parasympathetic
(auriculotemporal). Na, K, and amylase concentrations resembled closely the
composition of saliva obtained directly from the duct with electrical
stimulation of the parasympathetic nerve. These data provide the first
evidence that electrical stimulation of the parasympathetic nerve to
parotid and submandibular glands causes a mitogenic response in each of
these organs; the data also provide the first evidence that electrical
stimulation of the parasympathetic nerve causes an increase in levels of
the enzyme beta-1,4-galactosyltransferase, known to be implicated in
hyperplastic responses.
