Nicotine improves morphine-induced impairment of memory: Possible involvement of N-methyl-D-aspartate receptors in the nucleus accumbens

✍ Scribed by Shamseddin Ahmadi; Mohammad Reza Zarrindast; Ali Haeri-Rohani; Ameneh Rezayof; Maryam Nouri

• Publisher: Wiley (John Wiley & Sons)
• Year: 2007
• Tongue: English
• Weight: 170 KB
• Volume: 67
• Category: Article
• ISSN: 1932-8451
• DOI: 10.1002/dneu.20456

✦ Synopsis

Abstract

The possible involvement of N‐methyl‐D‐aspartate (NMDA) receptors in the nucleus accumbens (NAc) in nicotine's effect on impairment of memory by morphine was investigated. A passive avoidance task was used for memory assessment in male Wistar rats. Subcutaneous (s.c.) administration of morphine (5 and 10 mg/kg) after training impaired memory performance in the animals when tested 24 h later. Pretest administration of the same doses of morphine reversed impairment of memory because of post‐training administration of the opioid. Moreover, administration of nicotine (0.2 and 0.4 mg/kg, s.c.) before the test prevented impairment of memory by morphine (5 mg/kg) given after training. Impairment of memory performance in the animals because of post‐training administration of morphine (5 mg/kg) was also prevented by pretest administration of a noncompetitive NMDA receptor antagonist, MK‐801 (0.75 and 1 μg/rat). Interestingly, an ineffective dose of MK‐801 (0.5 μg/rat) in combination with low doses (0.075 and 0.1 mg/kg) of nicotine, which had no effects alone, synergistically improved memory performance impaired by morphine given after training. On the other hand, pretest administration of NMDA (0.1 and 0.5 μg/rat), which had no effect alone, in combination with an effective dose (0.4 mg/kg, s.c.) of nicotine prevented the improving effect of nicotine on memory impaired by pretreatment morphine. The results suggest a possible role for NMDA receptors of the NAc in the improving effect of nicotine on the morphine‐induced amnesia. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007.