title: Nitric oxide in the nucleus accumbens is involved in retrieval of inhibitory avoidance memory by nicotine.
abstract: In the present study, the possible effect of nitric oxide agents injected into the nucleus accumbens (NAc) in the presence or absence of nicotine on morphine state-dependent memory in adult male Wistar rats was investigated. As a model of memory, a step-through type inhibitory avoidance task was used. Post-training injection of morphine (4 and 6mg/kg) dose dependently induced the impairment of memory retention. Administration of morphine (4 and 6mg/kg) before retention induced state-dependent retrieval of the memory acquired under post-training morphine (6mg/kg) influence. Injection of nicotine before retention (0.25 and 0.5mg/kg) alone and nicotine (0.1, 0.25 and 0.5mg/kg) plus an ineffective dose of morphine (2mg/kg) reversed the post-training morphine-induced memory impairment. The amnesia elicited by morphine (6mg/kg) was also prevented by pre-retention intra-NAc administration of a nitric oxide synthase (NOS) inhibitor, l-NAME (0.24μg/rat, intra-NAc). Interestingly, an ineffective dose of nicotine (0.1mg/kg) in combination with low doses of l-NAME (0.06 and 0.12μg/rat, intra-NAc) synergistically improved memory performance impaired by morphine given after training. It is important to note that intra-NAc administration of l-NAME before retention impaired memory retrieval by itself. In contrast, pre-retention administration of l-arginine, a nitric oxide (NO) precursor (0.25 and 0.5μg/rat, intra-NAc), which had no effect alone, prevented the nicotine reversal of morphine effect on memory. The results suggest a possible role for nitric oxide of nucleus accumbens in the improving effect of nicotine on the morphine-induced amnesia and morphine state-dependent memory.
authors: Department of Neuroscience, School of Advanced Medical Technologies, Tehran University of Medical Sciences, Tehran, Iran. zarinmr@ams.ac.ir
authors: Mohammad Reza
authors: MR
authors: Zarrindast
authors: Morteza
authors: M
authors: Piri
authors: Mohammad
authors: M
authors: Nasehi
authors: Mohaddeseh
authors: M
authors: Ebrahimi-Ghiri
mesh_terms: D000647:Amnesia / Q000139:chemically induced / Q000523:psychology; D000701:Analgesics, Opioid / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000818:Animals; D001120:Arginine / Q000494:pharmacology; D001362:Avoidance Learning / Q000187:drug effects*; D003627:Data Interpretation, Statistical; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008297:Male; D008568:Memory / Q000187:drug effects*; D008845:Microinjections; D009020:Morphine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D009714:Nucleus Accumbens / Q000033:anatomy & histology / Q000502:physiology*; D011597:Psychomotor Performance / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000701:Analgesics, Opioid; D004791:Enzyme Inhibitors; D018722:Nicotinic Agonists; D009569:Nitric Oxide; D009538:Nicotine; D009020:Morphine; D001120:Arginine; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester