Fast cyclic voltammetry of oxidizable species; depth profile in the rat striatum with and without potassium stimulation of the median forebrain bundle.
Fast cyclic voltammetry was used to monitor the release of dopamine in the caudate nucleus following potassium stimulation of the median forebrain bundle and to determine the characteristics of the small basal oxidation current while dipping of an electrode with a large tip (0.3 mm) in the caudate nucleus. The oxidation current was shown to be greater just after the electrode reached the caudate area than at a time 15-20 s after its arrival. There was less current increase observed when the tip reached the cortex and no current was observed in the white matter or with the electrode returning or with repeated passage along the same track. Potassium stimulation of median forebrain bundle induced an initial low magnitude dopamine release which disappeared within minutes. The basal oxidation current increased step by step after a few potassium stimulations. This effect was not blocked by pargyline (75 mg/kg) whereas L-DOPA (200 mg/kg) was shown to increase it. It is thought that the large tip of the lowered electrode can destroy neurons and induce the release of intracellularly stored compounds into the extracellular space. We consider also dopamine to be responsible for the increase in oxidizable current just after the electrode movement stopped.
Yavich
L B
LB
Department of Neurology, University of Kuopio, Finland.
Airaksinen
M M
MM
Riekkinen
P J
PJ
D000818:Animals; D002421:Caudate Nucleus / Q000187:drug effects / Q000378:metabolism*; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D004563:Electrochemistry; D007700:Kinetics; D007980:Levodopa / Q000494:pharmacology; D008297:Male; D010084:Oxidation-Reduction; D010293:Pargyline / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology*; D016548:Prosencephalon / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains
D007980:Levodopa; D010293:Pargyline; D011188:Potassium; D004298:Dopamine