Nociceptin/orphanin FQ: actions within the brain.
A peptide termed nociceptin/orphanin FQ (N/OFQ) was recently identified as an endogenous agonist for the opioid receptor-like receptor currently specified as NOP receptor. Despite many structural homologies to the opioid system, the NOP receptor shows low-affinity binding to selective opioid agonists or antagonists. Vice versa, N/OFQ selectively activates the NOP receptor but not any opioid receptor subtype. This novel receptor/ligand system is widely expressed in the brain. At the cellular level, the actions of N/OFQ resemble those elicited by opioid peptides. The NOP receptor is coupled to G-proteins, whose activation results in inhibition of adenylate cyclase, modulation of calcium and potassium conductances, and regulation of transmitter systems. At the behavioral level, systemic application of N/OFQ elicits a unique range of responses, including a wide range of effects on pain processing such as hyperalgesia, analgesia, and allodynia, as well as anxiolytic actions, modulation of opioid-mediated processes, and influences on learning and memory.
Meis
Susanne
S
Institut für Physiologie, Medizinische Fakultät, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany. susanne.meis@medizin.uni-magdeburg.de
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001921:Brain / Q000187:drug effects / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D006801:Humans; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D018847:Opioid Peptides / Q000494:pharmacology / Q000502:physiology*; D011188:Potassium / Q000378:metabolism; D011957:Receptors, Opioid / Q000502:physiology*; D000094942:Nociceptin Receptor; D000097629:Nociceptin
D002118:Calcium; D018847:Opioid Peptides; D011188:Potassium; D011957:Receptors, Opioid; D000094942:Nociceptin Receptor; D000097629:Nociceptin; C000722283:OPRL1 protein, human