| ||NEURONAL SIGNALING DEPENDS on rapid changes in the electrical potential difference across the nerve cell membranes. Individual sensory cells can generate changes in membrane potential in response to very small stimuli: receptors in the eye respond to a single photon of light; olfactory neurons detect a single molecule of odorant; and hair cells in the inner ear respond to tiny movements of atomic dimensions. Signaling in the brain depends on the ability of nerve cells to respond to these small stimuli by producing rapid changes in the electrical potential difference across nerve cell membranes.
During an action potential the membrane potential changes quickly, up to 500 volts per second. These rapid changes in membrane potential are mediated by ion channels, a class of integral membrane proteins found in all cells of the body. The ion channels of nerve cells are optimally tuned for rapid information processing. The channels of nerve cells are also heterogeneous, so that different types of channels in different parts of the nervous system can carry out specific signaling tasks.
Because of this selective distribution of finely tuned functional elements, malfunctioning of iochannels in nerve and skeletal muscle can cause a wide variety of neurological diseases.Diseases due to ion channel malfunction are not limited to the brain. Cystic fibrosis and certain types of cardiac arrhythmia, for example, are also caused by ion channel malfunction. Moreover, ion channels are often the site of action of drugs, poisons, or toxins. Thus ion channels have crucial roles in both the physiology and the pathophysiology of he nervous system. In this talk we will introduce the subject of neural ionic channels. |
26 Dec. 2013
11:00 - 12:30