Opioid receptor affinities of kappa agonists, agonist/antagonists and antagonists in vitro and in vivo.
The CNS opioid receptors consist of a major triad: mu, delta and kappa. The kappa agonists presently available act as kappa agonists, delta antagonists and mu2 isoreceptor antagonists. Pure opiate antagonists possess a broad spectrum of activity at all 3 opioid receptor populations. The Ag/Ant analgesics also possess a broad spectrum of receptor affinities which awaits the definition of complex species differences in their actions. The design of more specific opioid agonists and antagonists will lead to a greater understanding of the many possible roles opioids serve within the CNS.
D000818:Animals; D001667:Binding, Competitive; D001921:Brain / Q000187:drug effects*; D009294:Narcotics / Q000494:pharmacology*; D009619:Nociceptors / Q000187:drug effects*; D051381:Rats; D011957:Receptors, Opioid / Q000187:drug effects*; D017465:Receptors, Opioid, delta; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu
D009294:Narcotics; D011957:Receptors, Opioid; D017465:Receptors, Opioid, delta; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu