Recepto-secretory mechanism in histamine-stimulated amylase release from rat parotid gland.

The recepto-secretory mechanism in histamine-stimulated amylase release from rat parotid slices was studied using blockers of receptors and inhibitors of the intracellular messenger systems. Amylase release stimulated by histamine was inhibited by pyrilamine, an H1-receptor blocker, but not by cimetidine, an H2-receptor blocker. Atropine, prazosin and yohimbine had no effect on the release. Histamine-stimulated amylase release was inhibited by W-7, ML-9 and H-7, inhibitors of a calmodulin, a myosin light chain kinase (MLCK) and protein kinase C, respectively, while H-8, an inhibitor of protein kinase A, did not inhibit the release. These results suggest that histamine stimulation evokes amylase release via H1-receptors, followed by the Ca2+-dependent systems involving calmodulin, MLCK and protein kinase C.