Enkephalins are small peptides that function as neurotransmitters in the brain and nervous system. They are part of the body's natural pain relief system and are involved in regulating pain, mood, and stress responses. Enkephalins bind to specific receptors, known as opioid receptors, which help modulate pain perception and emotional responses. These peptides are produced in various parts of the body, including the brain and spinal cord. Enkephalins play a crucial role in the body's response to stress and can promote feelings of well-being. Their action is similar to that of endorphins, which are also involved in pain relief and pleasure.