There are various devices on the market, all licensed for use by the FDA under the direction of a physician, which consist of two electrodes which are applied to various parts of the body, as in the treatment of lower back pain. These are called TENS units - TENS is an acronym for transient electro neural stimulation. There are many flavors of these devices, including devices that have been clinically shown to provide pain relief from the effects of the electrical currents they put through your body. The method by which these devices provide the sensation of pain relief has been the subject of much investigation. The surprising findings indicate that direct electrical stimulation of human body tissues evoke a release of various peptides.
Peptides are messenger molecules that have specific sites on cell surfaces to which they bind.
These sites, called receptor sites, are extraordinarily specific to individual peptides. It is remarkable that the body has a group of peptides called endorphin. These particular messenger molecules evoke a pain killing effect when they bind at their specific receptors. The opium family - morphine, heroin, codeine, etc. One theory of how electrical pain killing works, is that it induces the body to release its own endorphin.