Semichronic inhibition of glutathione reductase promotes oxidative damage to proteins and induces both transcription and translation of tyrosine hydroxylase in the nigrostriatal system.
We have evaluated the effect of N,N-bis (2-chloroethyl)-N-nitrosourea (BCNU), an inhibitor of glutathione reductase (GR), on the oxidative status along with the integrity of the nigrostriatal dopaminergic system of the rat. The oxidative status was studied by the quantification of carbonyl groups coupled to protein homogenates. Moreover, the specific oxidations in glial fibrillary acidic protein (GFAP) and neurofilament-200 (NF-200) were also measured. The results show that oxidative damage in proteins in the nigrostriatal system is confined to the striatum. Specific carbonyl groups coupled to native NF-200 and GFAP were also increased. These changes were accompanied by reactive astrocytosis in striatum but not in substantia nigra. In substantia nigra, decreased levels of dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) were observed following BCNU treatment. In contrast, DA levels were increased in the striatum along with an overall decrease in the ratios of DA metabolites to DA. We also studied the mRNA levels for tyrosine hydroxylase (TH) and the dopamine transporter (DAT) by in situ hybridization. TH mRNA but not DAT mRNA was significantly induced in substantia nigra following BCNU treatment, which was consistent with significant elevations in TH enzyme amount and activity and unchanged DA uptake in striatum. All these results support the DA free radical hypothesis and the key role of the striatal glutathione system in protecting the striatal system against oxidative stress.
Romero-Ramos
Marina
M
Departamento de Bioquímica, Bromatología, Toxicología y Medicina Legal, Facultad de Farmacia, Universidad de Sevilla, c/Profesor García Gonzalez s/n 41012-Sevilla, Spain.
Venero
Jose L
JL
Garcia-Rodriguez
Sonia
S
Ayala
Antonio
A
Machado
Alberto
A
Cano
Josefina
J
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002330:Carmustine / Q000494:pharmacology; D003342:Corpus Striatum / Q000378:metabolism / Q000473:pathology*; D004298:Dopamine / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000187:drug effects / Q000378:metabolism; D005980:Glutathione Reductase / Q000037:antagonists & inhibitors* / Q000187:drug effects; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins / Q000187:drug effects / Q000378:metabolism; D009419:Nerve Tissue Proteins; D016900:Neurofilament Proteins / Q000187:drug effects / Q000378:metabolism; D018384:Oxidative Stress; D010300:Parkinson Disease / Q000503:physiopathology; D014176:Protein Biosynthesis; D011506:Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D013378:Substantia Nigra / Q000378:metabolism / Q000473:pathology*; D014158:Transcription, Genetic; D014446:Tyrosine 3-Monooxygenase / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*
D050483:Dopamine Plasma Membrane Transport Proteins; D004791:Enzyme Inhibitors; D005904:Glial Fibrillary Acidic Protein; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D016900:Neurofilament Proteins; D011506:Proteins; D012333:RNA, Messenger; C493216:Slc6a3 protein, rat; D015102:3,4-Dihydroxyphenylacetic Acid; C051774:neurofilament protein H; D014446:Tyrosine 3-Monooxygenase; D005980:Glutathione Reductase; D002330:Carmustine; D004298:Dopamine