Enkephalins are neurotransmitters which work to suppress pain. The goal of pain suppression is to allow the body to cope with pain while remaining focused, rather than permitting the perception of pain to flood the system and cause panic, distress, or confusion. These neurotransmitters are polypeptides, meaning that they consist of very short chains of amino acids. Two different enkephalins have been identified: met-enkephalin and leu-enkephalin.
These neurotransmitters are released by the brain and central nervous system when the brain perceives pain. In addition to dulling the sensation of pain, typically in the short term, enkephalins also change the way in which people perceive pain. This can be important, as people can still be panicked or upset even when their pain is dulled, a problem which commonly occurs when people are given synthetic painkillers which allay pain without addressing underlying emotions.
Because these neurotransmitters can influence perception, they can also play a role in memory formation and mood. They can also influence appetite and the functioning of the digestive system. All of these physical and emotional changes can be beneficial for someone experiencing pain, making the release of enkephalins an important part of the body's response to sources of pain and injury. These polypeptides are classified as endorphins, among the family of compounds which create a “rush” in the body.
Researchers first began to identify these compounds and the way they work in the 1970s. Like the numerous other substances secreted by the body to transmit signals throughout the nervous systems, enkephalins are released automatically when the body senses that they are needed. People cannot control the timing or quantity of the release of a neurotransmitter, and the compound acts instantly to perform its function as soon as it is needed. The rapid response time involved can be critical for many neurotransmitters, as the circumstances in the body are constantly changing, making it important to send the right signal at the right time.
Enkephalins bind to the opioid transmitters in the body. This trait is what allows them to manage pain effectively, but it can also make them addictive. Numerous studies have demonstrated the addictive and behavior-modifying qualities of enkephalins, and these effects are greatly increased when people use synthetic painkillers which bind to the same receptors. Addictiveness is, in fact, a major concern when painkillers are administered to a patient, as a doctor wants to provide analgesics without making a patient dependent on them in the future.