The International Journal of Neuropsychopharmacology



Nicotine blocks stress-induced impairment of spatial memory and long-term potentiation of the hippocampal CA1 region


Abdulaziz M. Aleisa a1, Karem H. Alzoubi a1, Nashaat Z. Gerges a1 and Karim A. Alkadhi a1c1
a1 University of Houston, College of Pharmacy, Department of Pharmacological and Pharmaceutical Sciences, Houston, TX, USA

Article author query
aleisa am   [PubMed][Google Scholar] 
alzoubi kh   [PubMed][Google Scholar] 
gerges nz   [PubMed][Google Scholar] 
alkadhi ka   [PubMed][Google Scholar] 

Abstract

The effect of chronic nicotine treatment on chronic psychosocial stress-induced impairment of short-term memory and long-term potentiation (LTP) was determined. An ‘intruder’ stress model was used to induce psychosocial stress for 4–6 wk, during which rats were injected with saline or nicotine (1 mg/kg s.c.) twice a day. The radial arm water maze memory task was used to test hippocampus-dependent spatial memory. Chronic psychosocial stress impaired short-term memory without affecting the learning phase or long-term memory. Concurrent chronic nicotine treatment prevented stress-induced short-term memory impairment. In normal rats chronic nicotine treatment had no effect on learning and memory. Extracellular recordings from the CA1 region of anaesthetized rats showed severe reduction of LTP magnitude in stressed rats, which was normalized in nicotine-treated stressed rats. Nicotine had no effect on LTP in control animals. These results showed that chronic nicotine treatment improved hippocampus-dependent spatial memory and LTP only when impaired by stress.

(Received February 18 2005)
(Revised April 9 2005)
(Revised June 24 2005)
(Accepted June 24 2005)
(Published Online September 5 2005)


Key Words: Anaesthetized rat; dentate gyrus; fEPSP; neuroprotection; population spike; radial arm water maze.

Correspondence:
c1 Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, TX 77204-5037, USA. Tel.: (713) 743-1212 Fax: (713) 743-1229 E-mail: kalkadhi@uh.edu


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