Mu and delta opioid receptors diverge.
Contrary to current models, Scherrer et al. (2009) provide evidence that mu and delta opioid receptors are not expressed by the same pain-sensing neurons. In mice, agonists for these receptors produce analgesia restricted to either noxious heat or mechanical stimuli, implying that the receptors act on distinct fibers to mediate completely different types of pain relief.
Woolf
Clifford J
CJ
Neural Plasticity Research Group, Department of Anesthesia and Critical Care, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02129, USA. cwoolf@partners.org
D000701:Analgesics, Opioid / Q000494:pharmacology; D000818:Animals; D006358:Hot Temperature; D008465:Mechanoreceptors / Q000502:physiology; D051379:Mice; D009619:Nociceptors / Q000502:physiology; D010146:Pain; D017465:Receptors, Opioid, delta / Q000819:agonists / Q000502:physiology*; D017450:Receptors, Opioid, mu / Q000819:agonists / Q000502:physiology*
D000701:Analgesics, Opioid; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu