Nicotine restores morphine-induced amnesia via activation of dopamine D1 receptors in the nucleus accumbens
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Ronak Azizbeigi , Morteza Piri |
Islamic Azad University, Ardabil Branch , biopiri@iauardabil.ac.ir |
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Abstract: (7711 Views) |
Background: Drugs of abuse such as nicotine and morphine produce their effects through the stimulation of the mesolimbic dopaminergic pathway. Therefore, the present study aimed to evaluate the effect of pre-test injection of nicotine on morphine state-dependent learning as well as the effect of intra-nucleus accumbens (NAc) administration of D1 receptor antagonist on nicotine's effects in morphine state-dependent learning model. Materials and Methods: This experimental study was performed on 200 male rats. Rats were anesthetized with intra-peritoneal injection of ketamine hydrochloride plus xylazine and then placed in a stereotaxic frame. Two stainless-steel cannuale were placed in the NAc shell. The behavioral testing was started using an inhibitory avoidance task and afterwards the step-through latency of entering into the dark compartment was measured as a criterion for the assessment of memory. Results: Post-training injection of morphine induced amnesia. The post-training morphine-induced amnesia was restored by pre-test administration of the same doses of morphine and also nicotine. Moreover, the pre-test intra-NAc injection of SCH23390 prevented the nicotine reversal of morphine effect on memory. Conclusion: The results of this study suggest that the dopamine D1 receptor of the NAc may play an important role in improving the effect of nicotine on morphine-induced amnesia. |
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Keywords: Morphine, Nicotine, Dopamine D1 receptor, Nucleus accumbens, Inhibitory avoidance memory |
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Full-Text [PDF 297 kb]
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Type of Study: Research |
Subject:
medicine, paraclinic Received: 2012/10/15 | Revised: 2012/10/21 | Published: 2012/10/15
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