Potassium channels in gastrointestinal smooth muscle

1 Electromechanical coupling in smooth muscle serves to coordinate the cont ractile activity of the syncytium. Electrical activity of smooth muscle of the gut is generated by ionic conductances that regulate and in turn are re gulated by the membrane potential of smooth muscle cells. This activity det ermines the extent of Ca2+ entry into smooth muscle cells, and thus, the ti ming and intensity of contractions. 2 Potassium channels play an important role in regulating the excitability of the syncytium. The different types of K+ channel are characterized by di fferent sensitivities to membrane potential, to intracellular Ca2+ levels a nd to modulation by agonists. 3 This review highlights the different types of K+ channels found in gut sm ooth muscle and describes their possible roles in regulating the electrical activity of the muscle.