Hydrogen sulphide is a mediator of carrageenan-induced hindpaw oedema in the rat

Hydrogen sulphide (H2S) is a naturally occurring gas, with potent vasodilator activity. In this report, we identify a role for H2S in carrageenan-induced hindpaw oedema in the rat. Intraplantar injection of carrageenan ( 150 mu l, 2% ( w v (-1))) resulted in an increase in hindpaw H2S synthesising enzyme activity and increased myeloperoxidase ( MPO) activity. Pretreatment ( i.p. 60 min before carrageenan) with DL-propargylglycine ( PAG, 25 - 75 mg kg (-1)), an inhibitor of the H2S synthesising enzyme cystathionine-gamma- lyase (CSE), significantly reduced carrageenan-induced hindpaw oedema in a dose-dependent manner ( e. g. increase in hindpaw weight at 3 h, saline: 0.12 +/- 0.017 g; carrageenan, 1.39 +/- 0.037 g; PAG, 50 mgkg (-1), 1.11 +/- 0.06 g, n = 10) and MPO activity ( fold increase) in the hindpaw ( saline: 1.0 +/- 0.12; carrageenan, 2.92 +/- 0.45 g; PAG, 50mg kg(-1), 1.1 +/- 0.22, n = 10); PAG (50 mg kg(-1)) also inhibited H2S synthesising enzyme activity (nmol mg DNA (-1)) in the hindpaw in a dose-dependent manner (saline, 0.46 +/- 0.05; carrageenan, 0.71 +/- 0.08 g; PAG, 50 mgkg(-1), 0.17 +/- 0.05, n = 10).