Pharmacological mechanisms of opioid analgesics

GW Pasternak - Clinical neuropharmacology, 1993 - journals.lww.com
The description of multiple classes of opioid receptors has had a major impact on our
understanding of the mechanisms of analgesia. Three major classes of opioid receptors
have been defined: mu, kappa, and delta. The mu receptors have been further subclassified
into two distinct subtypes (mu1 and mu2), as have the delta receptors (delta1 and delta2).
Kappa receptors have been subdivided into kappa1, kappa2, or kappa3 subtypes. All of
these subtypes modulate pain perception, with the exception of the kappa2 receptor, which …