TENS (Transcutaneous Electrical Nerve Stimulation)
As a device, TENS's only function is to reduce pain and in animals, it does this by targeting the animal's natural opioids systems. Opioids come in two forms, the drugs that doctors prescribe and those that originate inside the animal, known as endogenous opioids. TENS results in an increase in these endogenous opioids in the spinal cord. After a period of time, the brain is not able to receive messages of pain. This is while there is an increased amount of opioids in their spinal cord.