Psychopharmacology

, Volume 100, Issue 1, pp 27–30

State dependent and/or direct memory retrieval by morphine in mice

  • Mika Nishimura
  • Yasuyuki Shiigi
  • Hiroshi Kaneto
Original Investigations

DOI: 10.1007/BF02245784

Cite this article as:
Nishimura, M., Shiigi, Y. & Kaneto, H. Psychopharmacology (1990) 100: 27. doi:10.1007/BF02245784

Abstract

Mice were trained in step-down and step-through type passive avoidance learning tasks and given retention tests. Pre-training administration of morphine impaired retention, the effect recovering completely after an additional injection of the same dose of morphine given 30 min before the retention test. Amnesia produced by scopolamine, cycloheximide and electroconvulsive shock was also reversed by pre-test morphine. Pre-test saline also reversed the morphine-induced memory impairment to some extent, indicating that the recovery may partially be due to the state dependent effect. Thus, it is demonstrated that pre-test morphine not only state dependently but also directly reversed memory impairment in mice.

Key words

MorphinePassive avoidanceMemory retrievalScopolamineCycloheximideECSNaloxoneMouse

Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • Mika Nishimura
    • 1
  • Yasuyuki Shiigi
    • 1
  • Hiroshi Kaneto
    • 1
  1. 1.Department of Pharmacology, Faculty of Pharmaceutical SciencesNagasaki UniversityNagasakiJapan