Potassium channels in gastrointestinal smooth muscle

1 Electromechanical coupling in smooth muscle serves to coordinate the contractile activity of the syncytium. Electrical activity of smooth muscle of the gut is generated by ionic conductances that regulate and in turn are regulated by the membrane potential of smooth muscle cells. This activity determines the extent of Ca²⁺ entry into smooth muscle cells, and thus, the timing 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 different sensitivities to membrane potential, to intracellular Ca²⁺ levels and to modulation by agonists. 3 This review highlights the different types of K⁺ channels found in gut smooth muscle and describes their possible roles in regulating the electrical activity of the muscle.