Effects of Hydrogen Sulphide on the Isolated Perfused Rat Heart

Objectives: hydrogen sulphide has been identified as a gas signalling molecule in the body, and has previously been shown to have vasorelaxant properties. the aim of the study was to investigate the effects of sodium hydrosulphide (nahs), a hydrogen sulphide donor, on heart rate (hr), left ventricular developed pressure (lvdp) and coronary flow (cf) in the isolated perfused rat heart. methods: a langendorff isolated heart preparation was used to investigate the effect of a dose range of sodium hydrosulphide, in the presence and absence of inhibitors, on heart rate, left ventricular developed pressure and coronary flow. results: sodium hydrosulphide caused a significant decrease in heart rate at a concentration of 10-3 m (p <0.001). this decrease was partially inhibited by glibenclamide, a katp channel blocker (p <0.05); l-name, a nitric oxide synthase inhibitor (p <0.001), and methylene blue (p <0.001), but not by h-89, a protein kinase a inhibitor. sodium hydrosulphide significantly increased coronary flow at concentrations of 10-4 – 10-3m (p <0.05). this response was significantly increased in the presence of l-name (p <0.001) and methylene blue (p <0.001), whereas h-89 inhibited the increase in coronary flow due to sodium hydrosulphide (p <0.001). sodium hydrosulphide significantly decreased lvdp at all concentrations (p <0.001).in the presence of glibenclamide and h-89, the time period of the decrease in lvdp due to sodium hydrosulphide was extended (p <0.001), whereas methylene blue and l-name caused a significant reduction in the response to sodium hydrosulphide (p <0.05, p <0.01 respectively). conclusion: sodium hydrosulphide reduced heart rate and lvdp, and increased coronary flow in the isolated perfused rat heart; however, the mechanisms of action could not be fully elucidated.