Histamine secretion induced by neuromedin-N

Area of Science:

• Pharmacology
• Immunology
• Physiology

Background:

• Neuromedin-N is a peptide with known biological activities.
• Histamine is a key mediator of inflammatory and allergic responses.
• Neurotensin is a related peptide with established effects on mast cells and vascular permeability.

Purpose of the Study:

• To investigate the effects of Neuromedin-N on histamine release from rat mast cells.
• To determine the impact of Neuromedin-N on skin vascular permeability in rats.
• To compare the potency of Neuromedin-N with neurotensin in these assays.

Main Methods:

• Isolated rat serosal mast cells were used to measure histamine release.
• In vivo studies involved intradermal injections of Neuromedin-N into rat skin.
• Vascular permeability was assessed by measuring plasma extravasation.
• The effect of mepyramine (an H1 antagonist) was evaluated.

Main Results:

• Neuromedin-N dose-dependently stimulated histamine release from mast cells.
• Histamine release was optimal between 30-37°C.
• Neuromedin-N increased skin vascular permeability in a dose-dependent manner.
• Neuromedin-N was 10 to 100 times less potent than neurotensin for both histamine release and vascular permeability.
• Mepyramine inhibited the vascular permeability response to Neuromedin-N.

Conclusions:

• Neuromedin-N stimulates histamine release from rat mast cells.
• The vascular effects of Neuromedin-N are mediated by histamine.
• Neuromedin-N is a less potent stimulator of histamine release and vascular permeability compared to neurotensin.