Participation of nitric oxide in mouse anaphylactic hypotension

Abstract

Mouse hen egg-white lysozyme-specific anaphylaxis was estimated by monitoring changes in blood pressure by using a tail-cuff method. Stimulation of histamine H 1 receptors of the vascular endothelium was suggested to be critical for mouse anaphylactic hypotension, because pretreatment with diphenhydramine but not with cimetidine completely inhibited the hypotension. Nitric oxide (NO) was indicated to play an important role in mouse anaphylaxis, because N G - nitro- L- argine methyl ester, a NO synthase inhibitor, significantly blocked the hypotension while a large amount of L-arginine, a precursor of NO synthesis, restored the hypotension.