title: Acute versus long-term effects of 6-hydroxydopamine on oxidative stress and dopamine depletion in the striatum of mice.
abstract: Oxidative stress is one of the mechanisms which may be important in the pathogenesis of Parkinson's disease. In the current study, the effects of 6-hydroxydopamine (6-OHDA) perfusion on hydroxyl radical formation in the mouse striatum were investigated using the in vivo salicylate trapping microdialysis technique. The latter uses salicylate as a trapping agent for hydroxyl radicals with formation of 2,3-dihydroxybenzoic acid (2,3-DHBA), which is measured by HPLC. Two different approaches of the technique were validated in mice. First, perfusion of the trapping agent salicylate (1 mM) via the probe in combination with 6-OHDA (5 μM) was used to screen for radical scavenging properties of compounds in mice. Alternatively, striatal administration of 6-OHDA in a concentration known to induce nigrostriatal denervation (1mM), without the trapping agent, allowed to maximally challenge the neuronal microenvironment and as such to investigate both its acute and long-term effects. In the first method, as expected, glutathione (GSH) (1.5 mM) prevented the 6-OHDA-induced increase in 2,3-DHBA levels. In the second method, GSH prevented the hydroxyl radical formation, while depletion of GSH with 2-cyclohexen-1-one (CHO) resulted in significantly higher 2,3-DHBA levels than when 6-OHDA was perfused alone. Three weeks after the local 6-OHDA perfusion, the total striatal dopamine (DA) and dihydroxyphenylacetic acid (DOPAC) content were reduced by 30%, compared to the intact striatum, accompanied by a reduction in striatal tyrosine hydroxylase (TH) immunoreactive (ir) nerve terminals. This suggests that the second method can be used to determine the acute as well as the long-term effects of 6-OHDA in the mouse striatum.
authors.affiliation: Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neuroscience, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Varcin
authors.forename: Eduard
authors.initials: E
authors.lastname: Bentea
authors.forename: Birgit
authors.initials: B
authors.lastname: Mertens
authors.forename: Chris Van Den
authors.initials: CV
authors.lastname: Haute
authors.forename: Veerle
authors.initials: V
authors.lastname: Baekelandt
authors.forename: Yvette
authors.initials: Y
authors.lastname: Michotte
authors.forename: Sophie
authors.initials: S
authors.lastname: Sarre
mesh_terms: D000208:Acute Disease; D000818:Animals; D002908:Chronic Disease; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D004298:Dopamine / Q000172:deficiency* / Q000378:metabolism; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D017551:Microdialysis / Q000379:methods*; D009498:Neurotoxins / Q000633:toxicity; D018384:Oxidative Stress / Q000187:drug effects* / Q000502:physiology; D016627:Oxidopamine / Q000633:toxicity*; D020734:Parkinsonian Disorders / Q000378:metabolism / Q000503:physiopathology; D013995:Time
chemical_list: D009498:Neurotoxins; D016627:Oxidopamine; D004298:Dopamine