Suranjana Gupta and Rohit Manchanda
SK ion channels, Hodgkin-Huxley model, action potential
There are a wide variety of ion channels present in smooth muscles that play a crucial role in regulating the excitability of the smooth muscle cell. Since calcium is a key regulator of muscle contraction, most of these channels work by either increasing or decreasing the calcium concentration within the cell. In smooth muscle, the initiation of an action potential (AP) occurs by the activation of voltage-gated calcium channels. The flow of calcium ions into the cell results in the activation of the calcium-activated potassium ion channels that repolarize and hyperpolarize the membrane. The characterization of these channels is complicated as these are a function of the dynamics of the sub-membrane calcium concentration. One of the relatively less understood calcium-activated potassium channels in smooth muscle is the small conductance potassium ion (SK) channel. This channel plays a crucial role in regulating the after-hyperpolarization phase (AHP), thereby controlling the frequency of spontaneous activity, or the firing rate. The paper discusses the computational modelling approach of this channel for the detrusor smooth muscle (DSM). The model has been created in a way that it can help us predict the nature of the sub-membrane calcium dynamics underlying the activation of the channel.