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- Title
Depression of retinogeniculate synaptic transmission by presynaptic D<sub>2</sub>-like dopamine receptors in rat lateral geniculate nucleus.
- Authors
Govindaiah, G.; Cox, Charles L.
- Abstract
Extraretinal projections onto neurons in the dorsal lateral geniculate nucleus (dLGN) play an important role in modifying sensory information as it is relayed from the visual thalamus to neocortex. The dLGN receives dopaminergic innervation from the ventral tegmental area; however, the role of dopamine in synaptic transmission in dLGN has not been explored. In the present study, whole cell recordings were obtained to examine the actions of dopamine on glutamatergic synaptic transmission. Dopamine (2–100 µm) strongly suppressed excitatory synaptic transmission in dLGN relay neurons that was evoked by optic tract stimulation and mediated by both N-methyl-d-aspartate and non -N-methyl-d-aspartate glutamate receptors. In contrast, dopamine did not alter inhibitory synaptic transmission arising from either dLGN interneurons or thalamic reticular nucleus neurons. The suppressive action of dopamine on excitatory synaptic transmission was mimicked by the D2-like dopamine receptor agonist bromocriptine (2–25 µm) but not by the D1-like receptor agonist SKF38393 (10–25 µm). In addition, the dopamine-mediated suppression was antagonized by the D2-like receptor antagonist sulpiride (10–20 µm) but not by the D1-like receptor antagonist SCH23390 (5–25 µm). The dopamine-mediated decrease in evoked excitatory postsynaptic current amplitude was accompanied by an increase in the magnitude of paired-pulse depression. Furthermore, dopamine also reduced the frequency but not the amplitude of miniature excitatory postsynaptic currents. Taken together, these data suggest that dopamine may act presynaptically to regulate the release of glutamate at the retinogeniculate synapse and modify transmission of visual information in the dLGN.
- Subjects
NEURAL transmission; NEURAL circuitry; NEUROPHYSIOLOGY; DOPAMINE receptors; NEUROTRANSMITTER receptors; LABORATORY rats; NEUROSCIENCES
- Publication
European Journal of Neuroscience, 2006, Vol 23, Issue 2, p423
- ISSN
0953-816X
- Publication type
Article
- DOI
10.1111/j.1460-9568.2005.04575.x