Neuroscience 2003 Abstract
| Presentation Number: | 461.20 |
|---|---|
| Abstract Title: | The intact mesoaccumbens dopamine projection in the brain slice: dopamine release and origin of the excitatory polysynaptic components. |
| Authors: |
Chuhma, N.*1,4
; Zhang, H.2
; Sulzer, D.1,2,4
; Rayport, S.1,3,4
1Dept. Psychiatry, Columbia Univ, New York, NY 2Dept. Neurol., Columbia Univ, New York, NY 3Dept. Anat. and Cell. Biol., Ctr. for NeuroBiol. and Behavior, Columbia Univ, New York, NY 4NY, 1051 Riverside Dr, Unit 62, 10032, |
| Primary Theme and Topics |
Synaptic Transmission and Excitability - Neurotransmitters -- Catecholamines |
| Secondary Theme and Topics | Motor Systems<br />- Basal Ganglia<br />-- Physiology of transmitters and receptors |
| Session: |
461. Catecholamines I Poster |
| Presentation Time: | Monday, November 10, 2003 4:00 PM-5:00 PM |
| Location: | Morial Convention Center - Hall F-I, Board # C2 |
| Keywords: | GLUTAMATE, VTA, AMPEROMETRY |
We prepared 500 µm horizontal brain slices from transgenic mice with fluorescent dopamine (DA) neurons (Zhuang et al, in press). Focal stimulation of the ventral tegmental area (VTA) evoked two kinds of glutamatergic transmission in the nucleus accumbens (nAcc); a monosynaptic early response with about 20 ms latency and a polysynaptic late response with more than 100 ms latency, as we described last year (SFN, 2002). To show that the DA system was intact in the slice, we measured DA release in the nAcc electrochemically. Local stimulation of the nAcc with 3 pulses at 100 Hz evoked 1.2 µM DA release. As we moved the stimulating electrode along the medial forebrain bundle (MFB) toward the VTA, the DA release decreased; focal VTA stimulation generated 30 nM release. These signals were enhanced by nomifensine (DA uptake blocker, 10 µM) confirming that they were due to DA release. In contrast to the early response, the late response appeared to be mediated polysynaptically via cortical inputs. This late response usually disappeared after 6-7 min stimulation. Stimulation of a wider area comprising both the VTA and SN with a larger bipolar electrode evoked a larger early response with the same latency as that induced by focal stimulation and a more stable late response. As the electrodes were moved laterally, closer to the area of dense cortical efferents, the late response increased. The late response was blocked completely by CNQX (40 µM) and disappeared after removal of cortex, as we described previously. These observations suggest that the late response is generated by antidromic activation of cortical neurons which synapse on other cortical neurons projecting to the nAcc.
Supported by Japan Society for the Promotion of Science (N.C.), NIDA (H.Z.,D.S.,S.R.)
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2003 Neuroscience Meeting Planner. New Orleans, LA: Society for Neuroscience, 2003. Online.
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