Histamine secretion induced by neuromedin-N.

Neuromedin-N dose-dependently stimulated the release of histamine from rat serosal mast cells and was 10 to 100 times less potent than neurotensin. The threshold concentration was 10(-6) M, and 10(-3) M neuromedin-N released 31% of the total cell histamine content. The histamine release induced by neuromedin-N was temperature-dependent with an optimum around 30-37 degrees C. Skin vascular permeability increased dose-dependently in response to intradermal injections of neuromedin-N and this peptide was 10 to 100 times less potent than neurotensin. Mepyramine inhibited the effect on vascular permeability suggesting that the effect of neuromedin-N was mediated via the release of histamine.