RESUMO
Carbon monoxide (CO) is one of a family of gas transmitters. In this article we present the results of mechanographic investigations of the mechanisms of CO action on a rat thoracic aorta segments. We found that relaxing effect of CO donor CORM-2 on vascular smooth muscles is mediated mainly by opening of voltage-dependent potassium channels in smooth muscle cells: 4-aminopyridine, blocking these channels, almost completely eliminated the CO-induced vasorelaxation of the segments precontracted by depolarization of the smooth muscle cells membranes with high potassium (30 mM KCl) solution or by phenylephrine (10 microM). For the first time we documented that CORM-2 reduces the nicardipine-sensitive input of 45Ca2+ in freshly isolated aorta cells. There are reasons to suggest that the L-type voltage-dependent calcium channels of vascular smooth muscle cells are another target for CO, which is implemented in the relaxing effect of this gas transmitter. Additional research is needed to determine the influence of ruthenium complexes (Ru(II)) on phenomenology of carbon monoxide effects.