What are the receptors that opioids primarily act on?

Opioids primarily act on mu, delta, and kappa receptors, which are types of opioid receptors found in the central nervous system and peripheral tissues. These receptors are G-protein coupled receptors that, when activated by endogenous peptides (like endorphins and enkephalins) or exogenous substances (like morphine and other opioids), initiate a range of physiological responses.

The mu receptors are primarily associated with analgesia (pain relief), euphoria, and respiratory depression, making them central to the therapeutic effects of opioids. Delta receptors are involved in modulating pain and can have mood-regulating effects. Kappa receptors also contribute to analgesia but can induce dysphoria and are important in the regulation of pain and stress responses.

This differentiation in receptor types relates to how various opioids can have different effects, side effects, and potential for addiction. Understanding the roles of these receptors helps in comprehending how opioids function as pain relievers and the basis for their therapeutic use and potential for abuse.