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Presynaptic dopamine D(4) receptor localization in the rat nucleus accumbens shell
A L Svingos1, S Periasamy, V M Pickel
1Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, NY 10021, USA. asvingos@mail.med.cornell.edu
Synapse (New York, N.Y.)
|May 20, 2000
Summary
Dopamine D(4) receptors are primarily located on presynaptic elements in the nucleus accumbens shell, influencing excitatory transmission. This finding is crucial for understanding psychostimulant effects and antipsychotic drug actions.
Area of Science:
- Neuroscience
- Cell Biology
- Pharmacology
Background:
- Dopamine D(4) receptors in the nucleus accumbens shell (AcbSh) are implicated in psychostimulant responses and antipsychotic efficacy.
- Their precise cellular localization and functional sites in this region remain to be fully elucidated.
Purpose of the Study:
- To determine the ultrastructural localization of dopamine D(4) receptors in the AcbSh.
- To investigate the functional sites of endogenous and exogenous D(4) receptor activation.
Main Methods:
- Electron microscopic immunocytochemistry was employed in rat brain.
- Dual-labeling with tyrosine hydroxylase (TH) was used to identify dopaminergic elements.
Main Results:
- D(4) receptors were predominantly found on axons and axon terminals (65%) within the AcbSh, with some on dendrites and spines (22%).
- Receptor labeling occurred on plasma membranes and vesicle membranes of axon terminals, some forming synapses.
- D(4) receptors were also present on dendritic spines receiving input from TH-positive terminals.
Conclusions:
- This study provides the first ultrastructural evidence for a significant presynaptic role of D(4) receptors in the AcbSh.
- A minor postsynaptic involvement is also suggested, contributing to dopaminergic modulation of excitatory transmission.