Role of nociceptin systems in learning and memory

This article summarizes our recent finding that the nociceptin system is in volved in the regulation of learning and memory. The nociceptin-knockout mi ce show greater learning ability in the water maze task, an enhanced latent learning in the water finding task, better memory in the passive avoidance task, and further, larger long-term potentiation in the hippocampal CA1 re gion than wild-type mice. Nociceptin itself induces an impairment of passiv e avoidance task in wild-type mice, which is reversed by naloxone benzoylhy drazone (NalBzoH). Thus, the nociceptin system seems to play negative roles in learning and memory, and NalBzoH may act as a potent antagonist for the nociceptin receptor. (C) 2000 Elsevier Science Inc. All rights reserved.