85 Role of Histamine in Mucin Secretion from Rat Submandibular Gland

• Published in: YONAGO ACTA MEDICA Vol. 38; no. 2; pp. 85 - 94
• Main Authors: Junji Fukumoto, Yoshinori Kamisaki, Tadao Itoh
• Format: Journal Article
• Language: Japanese
• Published: Tottori University Faculty of Medicine 1995
• ISSN: 0513-5710

The effects of histamine on mucin secretion from the rat submandibular gland were examined, and compared with those of β－adrenergic and cholinergic agonists. Histamine（1 mmol／L）elicited a 1. 7－fold increase in mucin secretion compared with that of the unstimulated control, while isoproterenol, carbachol and pilocarpine（0. 1mmol／L）caused 3. 3－, 1. 6－and 1. 3－fold increases, respectively. Histamine enhanced the effect of isoproterenol on mucin secretion from the submandibular gland although it influenced the effect of carbachol only slightly. The histamine－induced mucin secretion was inhibited by both H1 and H2 receptor antagonists. Furthermore, it was also reduced by atropine. Histamine did not directly mobilize intracellular calcium ion concentration levels but significantly increased the adenosine 3’, 5’－cyclic monophosphate（cAMP）level in the submandibular acini. The histamine－induced increase in cAMP was blocked by cimetidine. Impromidine, an H2 receptor agonist, stimulated mucin secretion, although the maximum effect was 38％ of that produced by histamine. These findings suggest that histamine is involved in the regulation of mucin secretion in the submandibular gland, probably through both mechanisms mediated by H1 and H2 receptors. The stimulation of H1 receptor may result in the release of acetylcholine from cholinergic nerve terminals, whereas the stimulation H2 receptor may cause an increase in cAMP in acinar cells to potentiate the mucin secretion.