Comparison of the effects of methanethiol and sodium sulphide on uterine contractile activity.

BACKGROUND

Our aim was to investigate the effect of methanethiol (CH3SH) on contractility of rat uterus and activities of redox-active enzymes, and to compare them with the effect of sodium sulphide (Na2S), a hydrogen sulphide (H2S/HS(-)) donor.

METHODS

Uteri were isolated from virgin Wistar rats, divided into six groups, controls (untreated uteri allowed to contract spontaneously and in the presence of Ca(2+)(6mM)), CH3SH treated (spontaneously active and Ca(2+) induced) and Na2S treated (spontaneously active and Ca(2+) induced). Underlying antioxidative enzyme activities (superoxide dismutase--SOD, glutathione peroxidase--GSHPx, glutathione reductase--GR) in CH3SH- or Na2S-treated uteri were compared to controls.

RESULTS

Our experiments showed that CH3SH and Na2S provoked reversible relaxation of both spontaneous and Ca(2+)-induced uterine contractions. The dose-response curves differed in shape, and CH3SH curve was shifted to higher concentration compared to H2S/HS(-). The effects of Na2S fitted sigmoid curve, whereas those of CH3SH fitted linearly. CH3SH provoked increased SOD activity and decreased GR activity. However, Na2S (H2S/HS(-)) provoked an increase in SOD activity exclusively in Ca(2+)-stimulated uteri, while the activity of GSHPx was increased in both types of active uteri.

CONCLUSION

Our results imply that CH3SH may have a constructive role in the control of muscle function and metabolism. Observed differences between CH3SH and H2S/HS(-) could be attributed to a larger moiety that is present in CH3SH compared to H2S, but they are more likely to be a consequence of the specific actions of HS(-), in relation to its negative charge.