Opioid receptor regulation.

Opioid receptors are regulated by multiple mechanisms, which are believed to contribute to the physiological plasticity of the endogenous opioid system in response to natural neuropeptides, as well as clinically relevant opiate drugs. Considerable progress has been made in elucidating molecular and cellular mechanisms of opioid receptor regulation. The article summarizes this progress by focusing on cell biological studies using cultured heterologous cell models and primary cultures of central nervous system neurons. These studies have identified multiple subcellular locations at which specific aspects of opioid receptor signaling and membrane trafficking are regulated. They have also identified unexpected regulatory effects of opiate drugs that may be relevant to pharmacotherapy.