Enhancement of spatial attention in nociceptin/orphanin FQ receptor- knockout mice

Takayoshi Mamiya, Yukihiro Noda, Miyuki Nishi, Hiroshi Takeshima, Toshitaka Nabeshima

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122 Citations (Scopus)


We isolated genes for the opioid receptor homologue MOR-C, namely nociceptin receptor (designated alternatively as orphanin FQ receptor) and generated nociceptin receptor-knockout mice. Previously, we have reported that the nociceptin system appears to participate in the regulation of the auditory system. However, the behavior of the nociceptin receptor-knockout mice has yet to be fully characterized. In the present study, we investigated changes in several behavioral performances in mice which lack nociceptin receptor. Nociceptive thresholds of nociceptin receptor-knockout mice were unchanged in the hot-plate and electric foot-shock tests as well as tail- flick and acetic acid-induced writhing tests compared to those of wild-type mice. The nociceptin receptor-knockout mice did not show any behavioral changes in the elevated plus-maze task. Surprisingly, in the water-finding test, the nociceptin receptor-knockout mice showed an enhanced retention of spatial attention (latent learning) compared to wild-type mice. In a biochemical study, dopamine content in the frontal cortex was lower in nociceptin receptor-knockout mice than wild-type mice. These results suggest that nociceptin receptor plays an important role in spatial attention by regulating the dopaminergic system in the brain.

Original languageEnglish
Pages (from-to)236-240
Number of pages5
JournalBrain Research
Issue number2
Publication statusPublished - 02-09-1998
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology


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