Inhibitory effect of ketotifen on mast cell degranulation in rat mesenteric microcirculation

• Published in: Japanese Journal of Pharmacology Vol. 67; no. suppl.2; p. 288
• Main Authors: Kimura, Masaaki, Bando, Tsutomu, Mitani, Hironohu, Totsuka, Tetsuya, Hayashi, Shigehiro
• Format: Journal Article
• Language: English
• Published: The Japanese Pharmacological Society 1995
• ISSN: 0021-5198; 1347-3506
• DOI: 10.1016/S0021-5198(19)47118-7

Mast cell degranulation was induced by nitric oxide synthesis inhibitor, N^G -nitro-L-arginine methyl ester (L-NAME) in microcirculation. Effects of mast cell modulators with peroral administration were examined. Intravital microscopy was used to examine the mast cell degranulation near microvessels in rat mesentery. The percentage of mast cell degranulation within 30 μm distance from the microvessels was assessed at 1.5 h after intravenous injection of L-NAME (30 mg/kg). Fully and partly degranulated cells were distinguished. Administration of L-NAME elicited the mast cell degranulation to a extent of 80% incidence. Peroral treatment with ketotifen at a dose of 1 mg/kg reduced the L-NAME-induced degranulation of mast cells to 20% incidence. It is conceivable that L-NAME permits injurious oxygen radical(s) to increase, and subsequently elicits mast cell degranulation, whereas ketotifen exerts against the increase or protects the cell from the injurious stimulation.