Action Potential (AP): Definition, History and References
Action potential (AP) is an electrical signal that is generated by an excitable cell in response to a stimulus. It is a transient electrical event, which is generated by the movement of ions across the cell membrane. Action potentials are commonly found in neurons, muscle cells, and endocrine cells. They are responsible for the transmission of electrical signals throughout the body, allowing for communication between cells and organs.
The history of action potentials began in the 19th century. In 1852, German physiologist Hermann von Helmholtz described the electrical properties of nerves. He found that nerve cells had the ability to conduct electricity and, therefore, could transmit signals. In the early 20th century, British physiologist Augustus D. Waller was the first to describe the action potential of a nerve. In his work, he noted the shape of the action potential and the direction of the current as it traveled along a nerve.
In the 1950s, Alan Hodgkin and Andrew Huxley conducted a series of experiments on the giant squid axon. This research provided a detailed description of the action potential, including the role of sodium and potassium ions in the generation and propagation of the electrical signal. Their work earned them the Nobel Prize in Physiology or Medicine in 1963.
Today, action potentials are studied in the fields of neuroscience, physiology, and biophysics. They are essential components of communication between cells, and are involved in a variety of physiological processes. Research in this area continues to shed light on the mechanisms of action potentials and their role in the body.
References
Hodgkin, A.L. & Huxley, A.F. (1952). A quantitative description of membrane current and its application to conduction and excitation in nerve. The Journal of Physiology, 117(4), 500-544.
Waller, A.D. (1880). On the electrical phenomena of the nervous system. The Journal of Physiology, 2(6), 433-460.
Helmholtz, H.V. (1852). On the sensations of tone as a physiological basis for the theory of music. Leipzig: Breitkopf & Hartel.
Petersen, C.C., & Grunnet, M. (2018). Action potentials in neuroscience: From single neurons to brain networks. Neuron, 97(4), 647-657.