Involvement of CB1 receptors in the ventral tegmental area in the potentiation of morphine rewarding properties in acquisition but not expression in the conditioned place preference model
| Autor: | Pariya Shaigani, Ali Rashidy-Pour, Pouyan Pahlevani, Anoumid Vaziri, Abbas Haghparast, Leila Zarepour, Abbas Ali Vafaei |
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| Rok vydání: | 2013 |
| Předmět: |
Male
Agonist AM251 medicine.drug_class Morpholines medicine.medical_treatment Motor Activity Naphthalenes Pharmacology Behavioral Neuroscience Piperidines Receptor Cannabinoid CB1 Reward Dopamine medicine Animals Rats Wistar Morphine Chemistry musculoskeletal neural and ocular physiology Ventral Tegmental Area Dopaminergic Association Learning Conditioned place preference Benzoxazines Rats Analgesics Opioid Ventral tegmental area medicine.anatomical_structure nervous system Opioid Conditioning Operant Pyrazoles Cannabinoid psychological phenomena and processes medicine.drug |
| Zdroj: | Behavioural Brain Research. 247:259-267 |
| ISSN: | 0166-4328 |
| Popis: | The ventral tegmental area (VTA) is a critical part of the brain reward system and has been engaged in mediating rewarding actions. CB1 receptors are one of the receptors that mediate the actions of cannabinoids and endocannabinoids in the central nervous system. Our aim was to determine the potentiating effects of CB1 receptors within the VTA in the acquisition and expression of morphine conditioned place preference (CPP). Stereotaxic surgery was performed bilaterally on each rat to administrate WIN55,212-2 (1, 2 and 4 mmol/0.3 μl DMSO) as CB1 receptor agonist and AM251 (15, 45 and 90 mmol/0.3 μl DMSO) as CB1 receptor antagonist. A three-compartment apparatus was used for the CPP test. The results showed that two doses of WIN55,212-2 (2 and 4 mmol) potentiates the rewarding effects of ineffective dose of morphine (2 mg/kg). We did not see any significant difference between any other doses of WIN55,212-2 and vehicle in the group which received the effective dose of morphine (5mg/kg). Additionally, conditioning scores decreased significantly with the highest administrated dose of AM251 (90 mmol) compared to the vehicle group. We did not observe any significant differences in the experiments for CPP expression by WIN55,212-2 or AM251. It seems that the cannabinoid and opioid systems are in interaction with each other and affect dopaminergic and/or non-dopaminergic neurons in the VTA. Blockade of CB1 receptors may increase GABA release, resulting in the reduction of dopamine output followed by a decrease in the acquisition of morphine-induced CPP in rats. |
| Databáze: | OpenAIRE |
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