Neuroscience 2005 Abstract
| Presentation Number: | 563.3 |
|---|---|
| Abstract Title: | Fluctations of extracellular dopamine levels in the shell portion of the rat nucleus accumbens during cannabinoid self-administration. |
| Authors: |
Fadda, P.*1,2
; Scherma, M.1,2
; Spano, M. S.1,2
; Melis, V.1
; Salis, P.1
; Fattore, L.2,3
; Fratta, W.1,2,3
1Dept Neuroscience , Univ. of Cagliari, Monserrato-Cagliari, Italy 2Centre of Excellence , Univ. of Cagliari, Monserrato-Cagliari, Italy 3Italy, Cittadella Universitaria di Monserrato, 09042, |
| Primary Theme and Topics |
Disorders of the Nervous System - Addiction and Drugs of Abuse -- Cannabinoids |
| Session: |
563. Cannabinoids Poster |
| Presentation Time: | Monday, November 14, 2005 3:00 PM-4:00 PM |
| Location: | Washington Convention Center - Hall A-C, Board # UU80 |
| Keywords: | cannabinoid, dopamine, reward, microdialysis/self-administration |
Several evidence suggests that cannabinoids act upon the brain reward circuitry, namely the mesolimbic dopamine (DA) pathway, influencing drug-seeking and drug-taking behaviors in a manner strikingly similar to that of other abused drugs.
Passive administrations of Δ9-tetrahydrocannabinol (THC) and synthetic CB1 receptor agonist WIN 55,212-2 are reported to enahance extracellular DA overflow in the nucleus accumbens and other reward-related forebrain areas, as measured by in vivo brain microdialysis.
Few years ago we characterized a reliable model of cannabinoid intravenous self-administration (IVSA) in rats, in which animals were trained to self-administer the cannabinoid CB1 receptor agonist WIN 55,212-2 (12.5 μg/kg inf) under a fixed ratio (FR1) schedule of reinforcement (Fattore et al. 2001). In the present study we used this model to investigate the effect of active cannabinoid administration on the DA extracellular accumbal concentrations during cannabinoid IVSA.
DA levels were measured in perfusate samples collected every 10 min before, during and after a 2h session by a HPLC. Extracellular DA concentrations increased rapidly in the cannabinoid self-administering rats and fluctated 250-300% above baseline for the entire duration of the IVSA session. The DA values returned to the baseline during the 30 min after the cessation of cannabinoid agonist exposure.
These results demonstrate for the first time that cannabinoid self-administration by the rat is accompained by an enhanchement in DA release in the shell portion of the nucleus accumbens, confirming that in modulating cannabinoid-taking behaviour the mesolimbic DA pathway is as important as for other drugs of abuse.
Passive administrations of Δ9-tetrahydrocannabinol (THC) and synthetic CB1 receptor agonist WIN 55,212-2 are reported to enahance extracellular DA overflow in the nucleus accumbens and other reward-related forebrain areas, as measured by in vivo brain microdialysis.
Few years ago we characterized a reliable model of cannabinoid intravenous self-administration (IVSA) in rats, in which animals were trained to self-administer the cannabinoid CB1 receptor agonist WIN 55,212-2 (12.5 μg/kg inf) under a fixed ratio (FR1) schedule of reinforcement (Fattore et al. 2001). In the present study we used this model to investigate the effect of active cannabinoid administration on the DA extracellular accumbal concentrations during cannabinoid IVSA.
DA levels were measured in perfusate samples collected every 10 min before, during and after a 2h session by a HPLC. Extracellular DA concentrations increased rapidly in the cannabinoid self-administering rats and fluctated 250-300% above baseline for the entire duration of the IVSA session. The DA values returned to the baseline during the 30 min after the cessation of cannabinoid agonist exposure.
These results demonstrate for the first time that cannabinoid self-administration by the rat is accompained by an enhanchement in DA release in the shell portion of the nucleus accumbens, confirming that in modulating cannabinoid-taking behaviour the mesolimbic DA pathway is as important as for other drugs of abuse.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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