The time course of dopamine transmission in the ventral tegmental area. The Journal of neuroscience : the official journal of the Society for Neuroscience [J Neurosci] Journal article

Title	The time course of dopamine transmission in the ventral tegmental area.
Author(s)	Ford CP, Phillips PE, Williams JT
Institution	Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239, USA.
Source	J Neurosci 2009 Oct 21; 29(42):13344-52.
MeSH	Animals Biophysics Chelating Agents Dizocilpine Maleate Dopamine Dopamine Agonists Egtazic Acid Electric Stimulation Electrochemistry Excitatory Amino Acid Antagonists Female G Protein-Coupled Inwardly-Rectifying Potassium Channels GABA Antagonists Inhibitory Postsynaptic Potentials Male Mice Mice, Inbred DBA Neurons Patch-Clamp Techniques Phosphinic Acids Picrotoxin Propanolamines Quinoxalines Quinpirole Rhodamines Signal Transduction Statistics, Nonparametric Temperature Time Factors Ventral Tegmental Area
Abstract	Synaptic transmission mediated by G-protein coupled receptors (GPCR) is not generally thought to be point-to-point. To determine the extent over which dopamine signals in the midbrain, the present study examined the concentration and time course of dopamine that underlies a D(2)-receptor IPSC (D(2)-IPSC) in the ventral tegmental area. Extracellular dopamine was measured electrochemically while simultaneously recording D(2)-IPSCs. The presence of dopamine was brief relative to the IPSC, suggesting that G-protein dependent potassium channel activation determined the IPSC time course. The activation kinetics of D(2) receptor-dependent potassium current was studied using outside-out patch recordings with rapid application of dopamine. Dopamine applied at a minimum concentration of 10 mum for a maximum of 100 ms mimicked the IPSC. Higher concentrations applied for as little as 5 ms did not change the kinetics of the current. The results indicate that both the intrinsic kinetics of G-protein coupled receptor signaling and a rapidly rising high concentration of dopamine determine the time course of the IPSC. Thus, dopamine transmission in the midbrain is more localized then previously proposed.
Language	eng
Pub Type(s)	In Vitro Journal Article Research Support, N.I.H., Extramural Research Support, Non-U.S. Gov't
PubMed ID	19846722

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