title: 1-Methyl-4-phenylpyridinium accumulates in cerebellar granule neurons via organic cation transporter 3.
abstract: 1-Methyl-4-phenylpyridinium (MPP+), the toxic metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, induces apoptosis in cerebellar granule neurons (CGNs). We have tested the hypothesis that organic cation transporter (OCT) 3 mediates the accumulation and, hence, the toxicity of MPP+ in CGNs. CGNs in primary culture express OCT3 but do not express mRNA for OCT1, OCT2 or the dopamine transporter. Cerebellar astrocytes are negative for OCT3 protein by immunocytochemistry. [3H]MPP+ accumulation by CGNs exhibits first-order kinetics, and a Kt value of 5.3 +/- 1.2 micro m and a Tmax of 0.32 +/- 0.02 pmol per min per 106 cells. [3H]MPP+ accumulation is inhibited by corticosterone, beta-estradiol and decynium 22 with Ki values of 0.25 micro m, 0.17 micro m and 4.0 nm respectively. [3H]MPP+ accumulation is also inhibited by desipramine, dopamine, serotonin and norepinephrine, but is not affected by carnitine (10 mm), mazindol (9 micro m) or GBR 12909 (1 micro m). MPP+-induced caspase-3-like activation and cell death are prevented by pretreatment with 5 micro mbeta-estradiol. In contrast, the neurotoxic effects of rotenone are unaffected by beta-estradiol. Interestingly, GBR 12909 protects CGNs from both MPP+ and rotenone toxicity. In summary, CGNs accumulate MPP+ in manner that is consistent with uptake via OCT3 and the presence of this protein in CGNs explains their sensitivity to MPP+ toxicity.
authors.affiliation: Biophysics Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
authors.forename: Tiesong
authors.initials: T
authors.lastname: Shang
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Uihlein
authors.forename: Jennifer
authors.initials: J
authors.lastname: Van Asten
authors.forename: Balaraman
authors.initials: B
authors.lastname: Kalyanaraman
authors.forename: Cecilia J
authors.initials: CJ
authors.lastname: Hillard
mesh_terms: D015655:1-Methyl-4-phenylpyridinium / Q000493:pharmacokinetics* / Q000633:toxicity; D018759:Adrenergic Uptake Inhibitors / Q000494:pharmacology; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology; D003345:Corticosterone / Q000494:pharmacology; D003891:Desipramine / Q000494:pharmacology; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004336:Drug Antagonism; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D008297:Male; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018696:Neuroprotective Agents / Q000494:pharmacology; D027701:Organic Cation Transport Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010879:Piperazines / Q000494:pharmacology; D011804:Quinolines / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D012402:Rotenone / Q000633:toxicity; D013696:Temperature; D000099254:Organic Cation Transporter 3
chemical_list: D015655:1-Methyl-4-phenylpyridinium; D018759:Adrenergic Uptake Inhibitors; D000893:Anti-Inflammatory Agents; D003345:Corticosterone; D003891:Desipramine; D018765:Dopamine Uptake Inhibitors; D004958:Estradiol; D018696:Neuroprotective Agents; D027701:Organic Cation Transport Proteins; D010879:Piperazines; D011804:Quinolines; D012333:RNA, Messenger; D012402:Rotenone; D000099254:Organic Cation Transporter 3; C100254:pseudoisocyanine; C043425:vanoxerine