The effects of histamine, pyrilamine, cimetidine, and ranitidine on secretion of lingual lipase and amylase from rat von Ebner's glands

Abstract

Minced von Ebner's glands of rat tongue were incubated in vitro with histamine and histamine receptor antagonists. At various time intervals, media and homogenates of the tissue were assayed for lingual lipase and amylase activity and percentage secretion calculated. Histamine elicited moderate secretion (approximately 10%) of lingual lipase and amylase. In contrast, pyrilamine, an H1 receptor antagonist, elicited > 60% secretion. There were statistically significant differences between the percentage secretion of lingual lipase and amylase for basal secretion, as well as for histamine- and pyrilamine-evoked secretion above basal. The H2 receptor inhibitors, cimetidine and ranitidine, stimulated secretion of only amylase, but not lingual lipase. When combined with histamine, these antagonists partially inhibited only the secretion of histamine-evoked lingual lipase, but not amylase. The differences in percentage secretion between the two enzymes indicate that exocytosis may not be the only process involved in protein secretion. The anomalous effects of the H1 and H2 receptor antagonists necessitate a more detailed characterization of the receptors of von Ebner's glands.

Effect of Substance P and Receptor Antagonists on Secretion of Lingual Lipase and Amylase from Rat von Ebner's Gland

“…If exocytosis was the only pathway of secretion, these slopes should have been identical. Similar differences were also seen when the secretion was stimulated by carbachol (12), isoproterenol (12), and histamine (10). The only explanation for these findings is that factors other than exocytosis may be involved in basal or stimulated secretion of these enzymes.…”

“…To a lesser extent protein secretion from von Ebner's gland is evoked by badrenergic stimulation but not by a-adrenergic stimulation (12). Histamine also stimulates protein secretion from von Ebner's gland (10).…”

“…These experiments were carried out as previously described, with some modifications (10,12). Sprague-Dawley male rats, 200 { 30 g, were obtained either from Charles River Laboratories, Raleigh, NC, certified free of sialodacryoadenitis and rat corona viruses or from their progeny in the breeding colony at the DVA Medical Center.…”

“…Incubations were done as described previously ( 10,12 ) with some changes. The tubes were centrifuged to 240 1 g and the media aspirated and discarded.…”

Histaminergic modulation of hormonal control in the exocrine guineapig pancreas

“…On the other hand, recent studies have demonstrated that histamine, a powerful stimulant of gastric secretion [2], has a marked secretagogue effect on the exocrine pancreas [3][4][5][6][7][8][9] and on other exocrine secretory glands [10,11]. Exogenous histamine has stimulatory effects on pancreatic secretion in anaesthetised dog [12,13] and rabbit [5,6] and in the isolated dog pancreas [4], but it is less effective in the anaesthetised rat (9).…”