Neuroscience 2005 Abstract
| Presentation Number: | 1026.16 |
|---|---|
| Abstract Title: | Effects of cocaine on the adolescent and adult brains: a pharmacological MRI study. |
| Authors: |
Chen, I.*1,2
; Xu, H.1,2,3
; Ren, J.1,2
; Rosen, B. R.1,2
; Jenkins, B. G.1,2
1Dept Radiol, Massachusetts General Hospital, Charlestown, MA 2Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 3China, Rm 2301 NMR Ctr Bldg 149, 02129, |
| Primary Theme and Topics |
Disorders of the Nervous System - Addiction and Drugs of Abuse -- Psychostimulants and development |
| Secondary Theme and Topics | Disorders of the Nervous System<br />- Addiction and Drugs of Abuse<br />-- Addiction: Neurobiology |
| Session: |
1026. Drugs of Abuse: Psychostimulants and Development Poster |
| Presentation Time: | Wednesday, November 16, 2005 4:00 PM-5:00 PM |
| Location: | Washington Convention Center - Hall A-C, Board # UU76 |
| Keywords: | cocaine, dopamine, adolescence, MRI |
During adolescence, the dopaminergic system in the brain is undergoing dramatic processing that includes synaptic pruning and alteration in dopaminergic receptor numbers. We used phMRI to investigate the differences in neuronal responses to acute cocaine challenge in the adolescent and adult brain.
Methods – Adolescent (22 days old, P22, n=7) and adult (>60 days old, n=6) Sprague-Dawley rats were used in this study. Rats were scanned in a 9.4T Bruker scanner under 1% halothane anesthesia with an acute cocaine challenge (0.5mg/kg, i.v.). Regional cerebral blood volume (rCBV) changes were assessed by using IRON method with echo planar imaging sequence (TR/TE 10ms/6ms). Dopamine (DA) release by microdialysis was assessed in the caudate/putamen in a separate group of P22 rats.
Results – Cocaine challenge on the adult rats induced bi-phasic rCBV changes (negative followed by positive rCBV changes) in the caudate/putamen (CPU), Nucleus accumbens (NAc), medial prefrontal cortex (mPFC), and thalamus. Cocaine challenge on the P22 rats induced rCBV decreases in the CPU, NAc, mPFC, and thalamus. The duration of rCBV decrease in the P22 rats was longer but the rCBV amplitude is similar to the negative component of rCBV changes in the adult rats. Microdialysis measurement in the CPU of the P22 rats showed an increase in DA release to cocaine challenge. The decoupling of the cocaine-induced rCBV response and DA release in the P22 rats indicates that the rCBV measurement is more tied to the post-synaptic function. For the P22 rats, the dopaminergic function is not yet as dominated by the D1 receptor (receptor function: D2>D1) as observed later in the adult brain (receptor function: D2<D1).
Methods – Adolescent (22 days old, P22, n=7) and adult (>60 days old, n=6) Sprague-Dawley rats were used in this study. Rats were scanned in a 9.4T Bruker scanner under 1% halothane anesthesia with an acute cocaine challenge (0.5mg/kg, i.v.). Regional cerebral blood volume (rCBV) changes were assessed by using IRON method with echo planar imaging sequence (TR/TE 10ms/6ms). Dopamine (DA) release by microdialysis was assessed in the caudate/putamen in a separate group of P22 rats.
Results – Cocaine challenge on the adult rats induced bi-phasic rCBV changes (negative followed by positive rCBV changes) in the caudate/putamen (CPU), Nucleus accumbens (NAc), medial prefrontal cortex (mPFC), and thalamus. Cocaine challenge on the P22 rats induced rCBV decreases in the CPU, NAc, mPFC, and thalamus. The duration of rCBV decrease in the P22 rats was longer but the rCBV amplitude is similar to the negative component of rCBV changes in the adult rats. Microdialysis measurement in the CPU of the P22 rats showed an increase in DA release to cocaine challenge. The decoupling of the cocaine-induced rCBV response and DA release in the P22 rats indicates that the rCBV measurement is more tied to the post-synaptic function. For the P22 rats, the dopaminergic function is not yet as dominated by the D1 receptor (receptor function: D2>D1) as observed later in the adult brain (receptor function: D2<D1).
Supported by NIH PO1 AT002048;1R01 DA16187-01 ; 5P01 DA09467-09
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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