MOLECULAR REGULATION OF OPIOID RECEPTORS

Opioid actions are initiated at membrane receptors which couple to cel lular effecters through G protein-mediated pathways, In the central ne rvous system opioids reduce neuronal activity through the inhibition o f voltage-dependent Ca2+ channels, the activation of K+ channels and t he inhibition of adenylyl cyclase. A significant clinical limitation t o opioid therapy is the development of tolerance, a biological event t hat has been linked to agonist effects at the receptor level. Molecula r studies on the consequences of opioid receptor regulation will provi de a better understanding of the cellular mechanisms involved in the a gonist-mediated events in tolerance development.