Evidence for and against a role for the OFQ/N/NOP1 system in the tonic control of nociceptive thresholds under basal conditions
| Yes |
| 1) I.c.v. administration of antisense oligonucleotides directed at NOP1 mRNA is analgesic (Meunier et al., 1995; Zhu et al., 1996, 1997; Rossi et al., 1997). |
| 2) I.c.v. administration of the antagonist [Nphe1]nociceptin(1–13)NH2 is analgesic on the 48°C hot water tail-withdrawal test (Calo' et al., 2000b). |
| 3) Intracerebroventricular administration of the antagonist JTC-801 is analgesic (Shinkai et al., 2000). |
| 4) Koster and colleagues' (1999) ppOFQ/N knockouts display increased baseline tail-withdrawal latencies. |
| No |
| 1) NOP1transgenic knockouts do not display altered nociceptive thresholds (Nishi et al., 1997; Ueda et al., 1997, 2000; Noda et al., 1998). |
| 2) Intracerebroventricular administration of the antagonist [Nphe1]nociceptin(1–13)-NH2 isnot analgesic on the 55°C hot water tail-withdrawal test (Calo' et al., 2000b). |
| 3) Intracerebroventricular administration of the antagonist J-113397 is not analgesic (Ozaki et al., 2000a). |
| 4) Chen and colleagues' (1999)ppOFQ/N knockouts display decreased baseline tail-withdrawal latencies (see above). |