Influence of molsidomine on thiol-groups of mitochondrial membranes

The active metabolite of molsidomine (N-carboxy-3-morpholino-sydnonimine-ethylester, Corvaton), SIN-1 (3-morpholinosydnone imine), from 5 nmolar concentration onward, unmasks SH-groups of rat heart mitochondrial membranes. By comparison, the organic nitrate isosorbide dinitrate was found to mask the SH-groups of rat heart mitochondria. In beef heart mitochondria, both antianginal substances decrease SH-group reactivity but to a different extent. Unmasking of mitochondrial SH-groups also did no longer occur in aged rat heart mitochondria. These findings may explain previous observations that for the formation of the guanylcyclase activating metabolite no thiol is necessary in the case of molsidomine, whereas organic nitrates need extra thiol for activation of guanylcyclase.