ABSTRACT
Transmembrane ion flux plays an important role in the control of membrane potential (Em) and contractility of pulmonary vascular smooth muscle, the end effector in the regulation of pulmonary vasomotor activity. Ion channels are integral membrane proteins possessing selective permeability for monovalent and divalent ions. The activity of ion channels is dependent on their biophysical characteristics, molecular composition, and physiological function. This chapter confronts the more practical aspects of determining ion channel activity and expression, including the direct measurement of transmembrane current flow in intact cells.
