Approaches for Investigating the Functional Significance of Transient Receptor Potential Cation Channels in Smooth Muscle Cells

This chapter aims to summarize experimental approaches and strategies useful for studying the impact of Transient Receptor Potential (TRP) channels on the regulation of smooth muscle cell (SMC) contractility and proliferation. It describes useful stratagems for identifying TRP channel expression patterns in SMCs and considers patch-clamp electrophysiological approaches for studying channel biophysics and regulation. Multiple TRP channel subunits are present in all tissues, but specific expression profiles vary widely between cell types. Selective pharmacological activators and inhibitors are commonly used to study the properties and physiological function of all ion channels, including TRP channels. The activity of single TRP channels that conduct currents with a high Ca²⁺ fraction can be optically recorded using total internal reflection fluorescence (TIRF) microscopy. TIRF microscopy relies on the generation of a low-energy evanescent illumination field when excitation light is completely reflected away from a glass surface supporting the sample.