ABSTRACT
Smooth muscles in the urogenital tract exemplify the amazing ability of these muscles to display quite different properties which fit them exquisitely to their separate functions. It is likely, for instance, that each muscle will have a unique combination of ion channels in its plasma membranes, which will govern its spontaneous electrical activity and its ability to respond to neurotransmitters and endogenous ligands. Amongst these channels will be the K channels, many types of which are expressed by smooth muscles. These channels will play an important role in determining the 'resting' membrane potential of the cells, the shapes and frequency of the spontaneous action potentials and the membrane response to receptor ligands. We do not yet know precisely which channels are present in which cells, but use of the increasing number of drugs and toxins that have been shown to modulate their activity, clearly demonstrates the importance of these channels. In this chapter, we will briefly describe the function and properties of urogenital smooth muscle, highlight the clinical problems, and discuss what is known about their K channels and the therapeutic potential of modifying K channel behaviour.
