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  • Poster presentation
  • Open Access

Effects of microinjections of nicotine into the dorsal hippocampus on morphine- induced amnesia

  • 1,
  • 1 and
  • 2
Annals of General Psychiatry20087 (Suppl 1) :S205

  • Published:


  • Nicotine
  • Morphine
  • Nicotinic Receptor
  • Cholinergic System
  • Dorsal Hippocampus


It has been shown that the dorsal hippocampus has an important role in the induction of reward-related learning by morphine [1]. Considering the hippocampal cholinergic system is critically involved in memory [2], the aim of this study was to evaluate the effects of bilateral microinjections of nicotine into the dorsal hippocampal CA1 regions on morphine-induced amnesia.

Materials and methods

A single-trial step-through passive avoidance task was used for the assessment of memory retention in male Wistar rats. Animals were bilaterally cannulated in the CA1 regions of the dorsal hippocampi by stereotaxic instrument, and were allowed to recover one week before behavioral testing.


Post-training subcutaneous (s.c.) injection of morphine dose-dependently induced impairment of memory retention, indicating morphine-induced amnesia. Intra-CA1 microinjections of different doses of nicotine, immediately before post-training administration of morphine dose-dependently inhibited morphine-induced amnesia. While, post-training bilateral microinjections of the same doses of nicotine into the CA1 regions alone did not affect memory retention.


The existing evidence supports that morphine dose- and time-dependently impairs retention of memory and thus exerts amnesic effects in the step-through passive avoidance task. Moreover, the results suggest a possible role for nicotinic receptors of the CA1 region of the dorsal hippocampus in the improving effect of nicotine on the morphine-induced amnesia.

Authors’ Affiliations

Department of Animal Biology, School of Biology, College of Science, University of Tehran, Tehran, Iran
Department of Pharmacology, School of medicine, Tehran University of Medical Sciences, Tehran, Iran


  1. Rezayof A, Zarrindast MR, Sahraei H, Haeri-Rohani A: Involvement of dopamine receptors of the dorsal hippocampus on the acquisition and expression of morphine-induced place preference in rats. J Psychopharmacol. 2003, 17: 415-423. 10.1177/0269881103174005.View ArticlePubMedGoogle Scholar
  2. Hasselmo ME, Bower JM: Acetylcholine and memory. Trends Neurosci. 1993, 16: 218-222. 10.1016/0166-2236(93)90159-J.View ArticlePubMedGoogle Scholar


© Khajepour et al; licensee BioMed Central Ltd. 2008

This article is published under license to BioMed Central Ltd.