title: A novel electrochemical approach for prolonged measurement of absolute levels of extracellular dopamine in brain slices.
abstract: Tonic dopamine (DA) levels influence the activity of dopaminergic neurons and the dynamics of fast dopaminergic transmission. Although carbon fiber microelectrodes and fast-scan cyclic voltammetry (FSCV) have been extensively used to quantify stimulus-induced release and uptake of DA in vivo and in vitro, this technique relies on background subtraction and thus cannot provide information about absolute extracellular concentrations. It is also generally not suitable for prolonged (>90 s) recordings due to drift of the background current. A recently reported, modified FSCV approach called fast-scan controlled-adsorption voltammetry (FSCAV) has been used to assess tonic DA levels in solution and in the anesthetized mouse brain. Here we describe a novel extension of FSCAV to investigate pharmacologically induced, slowly occurring changes in tonic (background) extracellular DA concentration, and phasic (stimulated) DA release in brain slices. FSCAV was used to measure adsorption dynamics and changes in DA concentration (for up to 1.5 h, sampling interval 30 s, detection threshold < 10 nM) evoked by drugs affecting DA release and uptake (amphetamine, l-DOPA, pargyline, cocaine, Ro4-1284) in submerged striatal slices obtained from rats. We also show that combined FSCAV-FSCV recordings can be used for concurrent study of stimulated release and changes in tonic DA concentration. Our results demonstrate that FSCAV can be effectively used in brain slices to measure prolonged changes in extracellular level of endogenous DA expressed as absolute values, complementing studies conducted in vivo with microdialysis.
authors: Department of Physiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland , Auckland 1142, New Zealand.
authors: Mark H
authors: MH
authors: Burrell
authors: Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721, United States.
authors: Christopher W
authors: CW
authors: Atcherley
authors: Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721, United States.
authors: Michael L
authors: ML
authors: Heien
authors: Department of Physiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland , Auckland 1142, New Zealand.
authors: Janusz
authors: J
authors: Lipski
mesh_terms: D012369:2H-Benzo(a)quinolizin-2-ol, 2-Ethyl-1,3,4,6,7,11b-hexahydro-3-isobutyl-9,10-dimethoxy- / Q000494:pharmacology; D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D002244:Carbon; D000077482:Carbon Fiber; D003042:Cocaine / Q000494:pharmacology; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D015259:Dopamine Agents / Q000494:pharmacology; D004558:Electric Stimulation / Q000295:instrumentation / Q000379:methods; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods*; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism*; D007980:Levodopa / Q000494:pharmacology; D008839:Microelectrodes; D010293:Pargyline / Q000494:pharmacology; D017208:Rats, Wistar; D046509:Tissue Culture Techniques / Q000295:instrumentation / Q000379:methods*
chemical_list: D000077482:Carbon Fiber; D015259:Dopamine Agents; D012369:2H-Benzo(a)quinolizin-2-ol, 2-Ethyl-1,3,4,6,7,11b-hexahydro-3-isobutyl-9,10-dimethoxy-; D007980:Levodopa; D002244:Carbon; D010293:Pargyline; D000661:Amphetamine; D003042:Cocaine; D004298:Dopamine
keywords: Electrochemistry; carbon-fiber microelectrodes; dopamine; in vitro; rat; striatum