Original Paper

Repeated Administration of Histamine Improves Memory Retrieval of Inhibitory Avoidance by Lithium in Mice
Mohammad Reza Zarrindast^a-c, Leila Parsaei^d, Shamseddin Ahmadi<sup>e

a</sup>Department of Pharmacology, School of Medicine and Iranian National Center for Addiction Studies, Tehran University of Medical Sciences,
^bInstitute for Studies in Theoretical Physics and Mathematics, School of Cognitive Sciences,
^cInstitute for Cognitive Science Studies,
^dDepartment of Basic Sciences, Tehran North Unit, Azad University, Tehran, and
^eDepartment of Biological Science and Biotechnology, Faculty of Science, University of Kurdistan, Sanandaj, Iran

Address of Corresponding Author

Pharmacology 2008;81:187-194 (DOI: 10.1159/000111760)

  Key Words

• Lithium
• Pyrilamine
• Ranitidine
• State-dependence learning
• Memory retrieval

  Abstract

The influence of repeated administration of histamine on lithium-induced state dependency has been investigated. A single-trial step-down inhibitory avoidance task was used to assess memory in adult male NMRI mice. Intraperitoneal (i.p.) administration of lithium (10 mg/kg), immediately after training (post-training), impaired inhibitory avoidance memory on the test day. Pre-test administration of lithium reversed amnesia induced by the drug given after training, with the maximum response at a dose of 10 mg/kg. Repeated intracerebroventricular (i.c.v.) administration of histamine (20 µg/mouse) for 3 consecutive days followed by 5 days of no drug treatment improved memory retrieval of inhibitory avoidance by a pre-test lower dose (5 mg/kg i.p.) of lithium. In contrast, 3 days of i.c.v. injections of both the histamine H1 receptor antagonist pyrilamine (40 µg/mouse) and the histamine H2 receptor antagonist ranitidine (6.25 and 12.5 µg/mouse) prevented the improving effect of pre-test lithium (10 mg/kg i.p.) on memory retrieval. The results suggest that the repeated administration of histaminergic agents may induce a sensitization which affects the memory impairment induced by lithium.

Copyright © 2008 S. Karger AG, Basel

  Author Contacts

M.R. Zarrindast
Department of Pharmacology, School of Medicine
Tehran University of Medical Sciences
PO Box 13145-784, Tehran (Iran)
Tel./Fax +98 21 6640 2569, E-Mail zarinmr@ams.ac.ir

  Article Information

This work was supported by a grant from Tehran University of Medical Sciences.

Received: April 23, 2007
Accepted: August 24, 2007
Published online: November 28, 2007
Number of Print Pages : 8
Number of Figures : 5, Number of Tables : 0, Number of References : 48