Neuroscience 2004 Abstract
| Presentation Number: | 807.9 |
|---|---|
| Abstract Title: | Reduction of the conditioned locomotor response following NMDA-induced lesions of the infralimbic cortex in rats sensitized to the dopamine agonist quinpirole. |
| Authors: |
Ray, L. B.*1
; Szechtman, H.1
1Psychiatry & Behvaioural Neurosci., McMaster Univ, Hamilton, Canada |
| Primary Theme and Topics |
Neurological and Psychiatric Conditions - Behavioral Pharmacology -- Other |
| Session: |
807. Monoamines II Poster |
| Presentation Time: | Tuesday, October 26, 2004 1:00 PM-2:00 PM |
| Location: | San Diego Convention Center - Hall A-H, Board # FFF8 |
| Keywords: | PSYCHOSTIMULANT DRUGS, D2/D3 RECEPTOR, MEDIAL PREFRONTAL CORTEX, SENSITIZATION |
Repeated administration of psychostimulant drugs produces behavioral sensitization and yields conditioned responses to cues associated with the drug-exposure environment. Such effects have been observed not only with indirect but also with direct dopamine agonists such as the D2/D3 receptor agonist quinpirole (QNP). A role for the medial prefrontal cortex in the expression of sensitization and conditioned locomotion has been suggested but less is known regarding the relevant region(s) within the prefrontal cortex, especially with regards to the expression of psychostimulant-induced conditioned responses. Here, we examined a role for the infralimbic prefrontal cortex (IPC) in the expression of locomotor sensitization to QNP and in the expression of conditioned locomotor activity.
Male rats received bi-weekly injections of QNP (0.5mg/kg sc x 10) or saline (SAL) and their locomotor activity monitored after each injection for 55 min on a large open-field (160 x 160 cm). Subsequently, rats underwent IPC neurotoxic lesions using NMDA (20mg/mL) or sham operations. After a one-week recovery period, rats received another injection of QNP or SAL to measure lesion effects on the expression of sensitization. The twelfth injection was the test for conditioned locomotor activity and all animals were administered SAL. Although currently based on a small sample size (N=6/group), results indicated that IPC lesions did not affect the expression of sensitized locomotion induced by QNP. However, IPC-lesion animals sensitized to QNP did show a significant reduction in the expression of conditioned locomotor activity compared to sham QNP-sensitized rats. No change in locomotor activity was identified in IPC-lesion animals that received chronic SAL injections. Results suggest that the expression of a conditioned locomotor response to QNP may be mediated by neurotransmission in the IPC.
Male rats received bi-weekly injections of QNP (0.5mg/kg sc x 10) or saline (SAL) and their locomotor activity monitored after each injection for 55 min on a large open-field (160 x 160 cm). Subsequently, rats underwent IPC neurotoxic lesions using NMDA (20mg/mL) or sham operations. After a one-week recovery period, rats received another injection of QNP or SAL to measure lesion effects on the expression of sensitization. The twelfth injection was the test for conditioned locomotor activity and all animals were administered SAL. Although currently based on a small sample size (N=6/group), results indicated that IPC lesions did not affect the expression of sensitized locomotion induced by QNP. However, IPC-lesion animals sensitized to QNP did show a significant reduction in the expression of conditioned locomotor activity compared to sham QNP-sensitized rats. No change in locomotor activity was identified in IPC-lesion animals that received chronic SAL injections. Results suggest that the expression of a conditioned locomotor response to QNP may be mediated by neurotransmission in the IPC.
Supported by CIHR (MOP-64424)
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2004 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2004. Online.
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