Effects of selective K+-channel agonists and antagonists on myoelectrical activity of a locus of the small bowel

Effects of Ca2+-activated K+ and voltage-activated K+-channel agonists and antagonists on the myoelectrical and contractile activity of a locus of the small bowel are simulated numerically. The model assumes that the electrical activity of smooth muscle syncytium is defined by kinetics of a mixture of L- and T-type Ca2+-channels, Ca2+-activated K+ and voltage-activated K+-channels, and leak Cl--channels, and that the smooth muscle syncytium of the locus is a null-dimensional contractile system. The results of modelling, both qualitatively and quantitatively, reproduce the effects of forskolin, lemakalim, phencyclidine, charybdotoxin and high concentration of external K+ ions, on gastrointestinal motility. This is confirmed by comparison with experimental observations conducted on the smooth muscle preparations of different species.