Neuroscience 2002 Abstract
| Presentation Number: | 322.10 |
|---|---|
| Abstract Title: | Mapping Dopamine Autoreceptors using Pharmacologic MRI. |
| Authors: |
Chen, Y. I.*1
; Choi, J. K.1
; Andersen, S. L.2
; Jenkins, B. G.1
1NMR, Mass General Hosp, Charlestown, MA 2Psychiatry, McLean Hospital, Belmont, MA |
| Primary Theme and Topics |
Synaptic Transmission and Excitability - Synaptic Transmission -- Presynaptic mechanisms |
| Secondary Theme and Topics | Synaptic Transmission and Excitability<br />- Neurotransmitters<br />-- Other |
| Session: |
322. Synaptic transmission: presynaptic mechanisms I Slide |
| Presentation Time: | Monday, November 4, 2002 3:15 PM-3:30 PM |
| Location: | Room 205A |
| Keywords: |
Regulation of dopamine release and synthesis is thought to occur via pre-synaptic dopamine(DA) D2 autoreceptors. Selective mapping of autoreceptors in vivo is difficult, as their function is best assessed using dynamic measures of DA release such as microdialysis. We show here that pharmacologic MRI (phMRI) may also prove useful for this purpose. First, we mapped the phMRI response to acute agonism and antagonism of D2 receptors using either quinpirole or eticlopride. These ligands lead to small change in relative cerebral blood volume (rCBV)(<10%) in stiratum (Str), nucleus accumbens (NAcc), and cingulate cortex. We then studied the response to an amphetamine (AMPH) challenge using pre- and post-treatment with eticlopride and quinpirole. Agonism of D2 receptors using quinpirole lead to a large decrease in rCBV changes induced by AMPH in Str and NAcc, but had little effect in frontal cortex (FCtx). Conversely, antagonism of D2 receptors with eticlopride lead to a large potentiation of rCBV changes induced by AMPH in NAcc and Str, and a slight antagonism of the rCBV changes in FCtx. The increase noted in NAcc (>2folds) was considerably larger than in Str (>1.5folds). This result accorded with microdialysis measurements made in a separate group of animals. These results suggest that phMRI can be used to map autoreceptor function. They further suggest that the autoreceptor role in both attenuating and potentiation DA release is more pronounced in NAcc than in Str. The relatively higher density of D3 receptors in Nacc suggests they may play a role in mediating this function. They also confirm numerous prior studies suggesting that the density of release-regulating autoreceptors is weaker in FCtx.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2002 Neuroscience Meeting Planner. Orlando, FL: Society for Neuroscience, 2002. Online.
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