TENS might help to relieve pain & spasm due to the effects that it has on the brain, nerves, muscles and neurotransmitters. As these are some of the things that are not working properly in MS due to demyelination, TENS may be beneficial.

In brief TENS causes:

1. Activation of opioid receptors may make the natural opioids, which are neurotransmitters that control pain in the brain more available and effective.

2. Reduction of excitation of nerves and excitory neurotransmitters which work to increase the strength and intensity of impulses to the target muscle groups may decrease spasm.

3. Increase of inhibitory neurotransmitters (GABA) in the brain and spinal cord may help to control spasms and reduce pain much like the medication Baclofen does.

4. Activation of inhibitory receptors may reduce pain by blocking the receptors that are activated by pain promoting neurotransmitters.

5. Increase of the release of serotonin and activation of serotonin receptors in the spinal cord may help to reduce pain.