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.