Electrophysiological Studies in Endocrine Cells
It was not so many years ago that electrical activity was thought to be the exclusive property of relatively specialized cells found in nerve and muscle. During this era, electrophysiology and neurophysiology were virtually synonymous. In the last 10 or 15 years, however, the vistas of electrophysiologists have broadened greatly. All cells in the body have resting potentials, which must have developed early in evolution to solve the osmotic problem that arises when substances are sequestered in the cytoplasm (Tosteson, 1964). Membrane potentials also had an early use in energy production. According to the Mitchell hypothesis (Mitchell, 1967), the immediate source of energy for the synthesis of ATP is a transmembrane electrochemical gradient of protons. Volume control and energy production were problems confronted by cells very early on, and membrane potentials must thus have been around for a long time, and nature has devised many ways to use them.
KeywordsCalcium Channel Sodium Channel Endocrine Cell Slow Component Sodium Current
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