Effects of histamine agonists and antagonists on rat peritoneal mast cells.

Abstract

histamine release from rat peritoneal mast cells (RPMC). Since inhibitory effects of these compounds could be reversed by thioperamide, but not by mepyramine or cimetidine, an H3-receptor dependent negative feedback mechanism on anaphylactic histamine release was proposed to exist in RPMC. However since dimaprit has no H3receptor stimulating activity in rat brain [3], these authors suggested that the postulated H3-receptors in mast cells are a subtype distinct from those in the brain. In contrast, Lau and Pearce [4] reported that dimaprit and another H2 agonist impromidine had no inhibitory activity on RPMC at concentrations <10 π5 M but instead induced histamine release at higher concentrations. Hence, we reinvestigated the effects of dimaprit and impromidine, and included the H3 agonist imetit for comparison. The effects of these three compounds on RPMC were further characterised with specific histamine receptor antagonists and benzalkonium chloride.