Abstract
Epithelial tissues play many roles in maintaining homeostasis of the human body. These tissues separate the body from the external environment (e.g., skin which protects the body), and of course, epithelial tissues separate body compartments, line the surfaces of organs, and line the inner surfaces of many hollow organs. Epithelial cells are polarized as there are specific transport proteins (ion channels and ion transporters) residing in the apical and basolateral membranes of the epithelial cells. Different epithelial cells perform specific functions in the regulation of absorption and secretion of ions, solutes, nutrients, and water. Understanding how these tissues (cells) function has been challenging and a number of techniques have been developed and/or adapted to study the functions of epithelial tissues and cells. Our ability to understand the physiology and the disease pathophysiology of epithelial tissues and cells is really reduced down to determining the fundamental characteristics and basic biology/physiology of the specific ion channels and ion transporters participating in overall epithelial transport physiology. This chapter provides a historical overview of various experimental techniques which have been instrumental and are still employed to discover intriguing aspects of epithelial ion transport physiology.