Characteristics of beta-endorphin-induced histamine release from rat serosal mast cells. Comparison with neurotensin, dynorphin and compound 48/80.

Rat peritoneal mast cells were exposed to the neurohormone and basic opioid peptide beta-endorphin. beta-Endorphin induced a dose-dependent release of histamine from the mast cells. A significant histamine release was found at 5 mumol/l of beta-endorphin and maximal release (35% of total) at 20 mumol/l. The histamine release process was very rapid and terminated within 30 s at 37 C, and in this sense is very similar to the histamine release induced by compound 48/80 or neurotensin. The histamine release was temperature-dependent showing an optimum release around 30 C, and it was independent of available extracellular calcium, but was inhibited in the presence of high extracellular calcium concentrations. Naloxone, only in very high concentrations (10 mmol/l), inhibited the release, and the very same concentration also inhibited the neurotensin - as well as the compound 48/80-induced histamine release. Cromoglycate and benzalkoniumchloride, a 48/80 antagonist, both produced a progressive dose-dependent inhibition of beta-endorphin-, neurotensin- as well as compound 48/80-induced histamine release. Taken together, the findings indicate that the opioid peptide beta-endorphin induces a selective, energy-dependent release of histamine from peritoneal rat mast cells. The pattern of release has much in common with that of compound 48/80 and other basic peptides, such as neurotensin and substance P. In addition this pattern of release is similar to that induced by dynorphin.