Histamine release induced by neurotensin from rat peritoneal mast cells

Neurotensin induced the release of histamine from both purified and non-purified rat peritoneal mast cells by a non-cytotoxic mechanism. It was effective at a concentration as low as 10(-8) M. The dose-response curve for the neurotensin effect was triphasic: and initial gentle rise, a plateau (2.5 X 10(-7) -2.5 X 10(-6) M) and a second rise. Disodium cromoglycate markedly, but benzalkonium chloride only slightly, inhibited the neurotensin-induced release. The effect of neurotensin was markedly different from that of substance P, bradykinin and compound 48/80 with respect to both the dose-response curve and the sensitivity to benzalkonium chloride. These inducers of histamine release showed somewhat different effects with changes in pH and temperature. Their actions did not require extracellular Ca2+. The results indicate that neurotensin is a potent histamine releaser acting directly on mast cells. Its mode of action may be different from those of the other substances tested.