Abstract
Nociceptin and nociceptin receptor, which show structural similarities to opioid peptides and opioid receptors, respectively, have been recently found to constitute a novel neuromodulatory system. In the central nervous system, however, the physiological role of modulation via the nociceptin receptor is still unclear. Here, we report the behavioral pharmacological characterization of mice lacking the nociceptin receptor. Nociceptin produced hyperalgesia and hypolocomotion, whereas the nociceptin receptor-knockout mice showed no significant abnormalities in nociceptive thresholds (tail- flick, hot-plate, electric, and acetic acid-induced writhing tests) and locomotion. In the learning and memory tests, nociceptin induced impairment of learning and memory in wild-type mice. Nociceptin receptor-knockout mice possessed greater learning ability and had better memory than wild-type mice. These results suggest that the nociceptin system plays a role in regulation of nociception or locomotion and seems to play negative roles in learning and memory. Next, we compared nociceptive responses induced by various opioids between the nociceptin receptor-knockout and wild-type mice. As previously reported, morphine (μ-opioid receptor agonist), U-50,488H (K1-opioid receptor agonist), and naloxone benzoylhydrazone (NalBzoH; K3-opioid receptor agonist) induced antinociceptive effects in wild-type mice. Surprisingly, knockout mice lacked the antinociceptive effect induced by NalBzoH, but not by morphine and U-50,488H. Further, NalBzoH completely inhibited nociceptin-induced hyperalgesia and hypolocomotion in wild-type mice. Experiments on the cultured cells transfected with the nociceptin receptor cDNA showed that NalBzoH competed in [3H]-nociceptin binding and attenuated the nociceptin-induced inhibition of cyclic AMP accumulation induced by forskolin. These results clearly suggest that NalBzoH acts as a potent antagonist for the nociceptin receptor. Our studies suggest that the nociceptive system and/or learning and memory processes could be modulated by ligands to the nociceptin receptor, and further that the antagonists are worth testing for the alleviation of pain and memory disorders.
| Original language | English |
|---|---|
| Pages (from-to) | 73-78 |
| Number of pages | 6 |
| Journal | Japanese Journal of Psychopharmacology |
| Volume | 19 |
| Issue number | 2 |
| Publication status | Published - 01-01-1999 |
| Externally published | Yes |
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- Medicine(all)
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Behavioral pharmacological characterization of mice lacking the nociceptin receptor. / Noda, Y.; Mamiya, T.; Nabeshima, T.
In: Japanese Journal of Psychopharmacology, Vol. 19, No. 2, 01.01.1999, p. 73-78.Research output: Contribution to journal › Short survey
TY - JOUR
T1 - Behavioral pharmacological characterization of mice lacking the nociceptin receptor
AU - Noda, Y.
AU - Mamiya, T.
AU - Nabeshima, T.
PY - 1999/1/1
Y1 - 1999/1/1
N2 - Nociceptin and nociceptin receptor, which show structural similarities to opioid peptides and opioid receptors, respectively, have been recently found to constitute a novel neuromodulatory system. In the central nervous system, however, the physiological role of modulation via the nociceptin receptor is still unclear. Here, we report the behavioral pharmacological characterization of mice lacking the nociceptin receptor. Nociceptin produced hyperalgesia and hypolocomotion, whereas the nociceptin receptor-knockout mice showed no significant abnormalities in nociceptive thresholds (tail- flick, hot-plate, electric, and acetic acid-induced writhing tests) and locomotion. In the learning and memory tests, nociceptin induced impairment of learning and memory in wild-type mice. Nociceptin receptor-knockout mice possessed greater learning ability and had better memory than wild-type mice. These results suggest that the nociceptin system plays a role in regulation of nociception or locomotion and seems to play negative roles in learning and memory. Next, we compared nociceptive responses induced by various opioids between the nociceptin receptor-knockout and wild-type mice. As previously reported, morphine (μ-opioid receptor agonist), U-50,488H (K1-opioid receptor agonist), and naloxone benzoylhydrazone (NalBzoH; K3-opioid receptor agonist) induced antinociceptive effects in wild-type mice. Surprisingly, knockout mice lacked the antinociceptive effect induced by NalBzoH, but not by morphine and U-50,488H. Further, NalBzoH completely inhibited nociceptin-induced hyperalgesia and hypolocomotion in wild-type mice. Experiments on the cultured cells transfected with the nociceptin receptor cDNA showed that NalBzoH competed in [3H]-nociceptin binding and attenuated the nociceptin-induced inhibition of cyclic AMP accumulation induced by forskolin. These results clearly suggest that NalBzoH acts as a potent antagonist for the nociceptin receptor. Our studies suggest that the nociceptive system and/or learning and memory processes could be modulated by ligands to the nociceptin receptor, and further that the antagonists are worth testing for the alleviation of pain and memory disorders.
AB - Nociceptin and nociceptin receptor, which show structural similarities to opioid peptides and opioid receptors, respectively, have been recently found to constitute a novel neuromodulatory system. In the central nervous system, however, the physiological role of modulation via the nociceptin receptor is still unclear. Here, we report the behavioral pharmacological characterization of mice lacking the nociceptin receptor. Nociceptin produced hyperalgesia and hypolocomotion, whereas the nociceptin receptor-knockout mice showed no significant abnormalities in nociceptive thresholds (tail- flick, hot-plate, electric, and acetic acid-induced writhing tests) and locomotion. In the learning and memory tests, nociceptin induced impairment of learning and memory in wild-type mice. Nociceptin receptor-knockout mice possessed greater learning ability and had better memory than wild-type mice. These results suggest that the nociceptin system plays a role in regulation of nociception or locomotion and seems to play negative roles in learning and memory. Next, we compared nociceptive responses induced by various opioids between the nociceptin receptor-knockout and wild-type mice. As previously reported, morphine (μ-opioid receptor agonist), U-50,488H (K1-opioid receptor agonist), and naloxone benzoylhydrazone (NalBzoH; K3-opioid receptor agonist) induced antinociceptive effects in wild-type mice. Surprisingly, knockout mice lacked the antinociceptive effect induced by NalBzoH, but not by morphine and U-50,488H. Further, NalBzoH completely inhibited nociceptin-induced hyperalgesia and hypolocomotion in wild-type mice. Experiments on the cultured cells transfected with the nociceptin receptor cDNA showed that NalBzoH competed in [3H]-nociceptin binding and attenuated the nociceptin-induced inhibition of cyclic AMP accumulation induced by forskolin. These results clearly suggest that NalBzoH acts as a potent antagonist for the nociceptin receptor. Our studies suggest that the nociceptive system and/or learning and memory processes could be modulated by ligands to the nociceptin receptor, and further that the antagonists are worth testing for the alleviation of pain and memory disorders.
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M3 - Short survey
C2 - 10464778
AN - SCOPUS:0032975015
VL - 19
SP - 73
EP - 78
JO - Neuropsychopharmacology Reports
JF - Neuropsychopharmacology Reports
SN - 1340-2544
IS - 2
ER -