In the in vitro experiences on the isolated rat aortic rings and urinary bladder strips the spasmolytic activity of the phosphodiesterase inhibitor drotaverine and the ATP-sensitive (KATP) potassium channel openers pinacidil and flocalin were studied. It was found that the KATP potassium channel opener pinacidil was the most effective in the phenilephrine precontracted isolated rat aortic rings (ЕС 50 (0.618±0.100) µМ); the flocalin caused 50% relaxation of urinary bladder strips at concentration (23.30±6.63) µМ and has no considerable effect on the vessels. The phosphodiesterase inhibitor drotaverin was the most effective at nonspecific constriction of isolated smooth muscle preparations. Our results can be taken into account when these drugs are used in clinic.
