Enkephalins

Definition

Enkephalins are endogenous opioid peptides produced in the brain and nervous system that function as neurotransmitters and neuromodulators. They are closely associated with the body's pain management and reward systems.

5 Must Know Facts For Your Next Test

1. Enkephalins bind to and activate the μ- and δ-opioid receptors, producing analgesic (pain-relieving) and euphoric effects.
2. The two main enkephalin peptides are met-enkephalin and leu-enkephalin, which differ by only one amino acid.
3. Enkephalins are synthesized from a larger precursor protein called proenkephalin and are inactivated by the enzyme enkephalinase.
4. Enkephalin release and activity is thought to be part of the body's natural pain management system, helping to modulate the perception of pain.
5. Dysregulation of the enkephalin system has been implicated in the development of opioid dependence and addiction.

Review Questions

• Describe the role of enkephalins in the body's pain management system.
  • Enkephalins play a key role in the body's natural pain management system by binding to and activating opioid receptors, particularly the μ- and δ-opioid receptors, in the central and peripheral nervous systems. This activation produces analgesic (pain-relieving) effects by modulating the transmission and perception of nociceptive (pain) signals. The enkephalin system is thought to be part of the body's endogenous mechanism for managing and reducing the experience of pain.
• Explain how the dysregulation of the enkephalin system can contribute to opioid dependence and addiction.
  • Enkephalins, as endogenous opioid peptides, activate the same receptors (μ- and δ-opioid receptors) as exogenous opioid drugs, such as prescription painkillers and heroin. Chronic exposure to exogenous opioids can lead to desensitization and downregulation of opioid receptors, as well as disruption of the normal functioning of the enkephalin system. This dysregulation can result in the development of tolerance, dependence, and addiction, as the brain becomes reliant on the presence of opioid compounds, whether endogenous or exogenous, to maintain normal function and experience feelings of reward and analgesia.
• Evaluate the potential therapeutic applications of targeting the enkephalin system for the treatment of pain and opioid use disorders.
  • The enkephalin system represents a promising target for the development of novel pain management and addiction treatment strategies. Enhancing the activity of endogenous enkephalins or developing synthetic enkephalin analogs that selectively activate opioid receptors could provide effective analgesia without the adverse effects and addiction liability associated with traditional opioid painkillers. Additionally, interventions that restore the normal functioning of the enkephalin system, such as inhibiting enkephalinase to prolong the action of endogenous enkephalins, may help mitigate the symptoms of opioid withdrawal and reduce the risk of relapse in individuals with opioid use disorders. Further research is needed to fully elucidate the therapeutic potential of targeting the enkephalin system in the management of pain and opioid-related problems.

Related terms

Endogenous Opioids:

Naturally occurring opioid compounds produced within the body, such as enkephalins, endorphins, and dynorphins, that bind to and activate opioid receptors.

Opioid Receptors: G-protein coupled receptors located throughout the central and peripheral nervous systems that bind to and are activated by opioid compounds, both endogenous and exogenous.

Nociception:

The neural processes of encoding and processing noxious stimuli that elicit the sensation of pain, which enkephalins help to modulate.