Enkephalins, one class of the body's natural opiates, are in the gut.

It was later found that there were "natural opiates," called enkephalins, which the body produces and uses to relieve pain and stress.

He said A drug based on the body's form of marijuana would use a completely different pain killing mechanism from that of the natural opiates.

Second, the discovery of the brain's natural opiates has triggered an explosion of interest in neurotransmitter pathways and functions.

And since the discovery of the body's natural opiates - endorphins and enkephalins - we've had a putative explanation.

Gate control theory led to the valuable discovery of endorphins and enkephalins, the body's natural opiates.

When animals and humans experience pain, their brains release natural opiates similar to morphine.

Opioids are narcotic pain medications that contain natural, synthetic or semi-synthetic opiates.

Scientists also isolated natural opiates called endorphins and enkephalins, substances made by the body but closely resembling painkilling drugs.

Experts say the natural opiates seem to produce pure pain relief, with no side effects.