Mesencephalic THmRNA-reduced expression by blocking axonal transport with colchicine.
Colchicine, an axonal transport blocking agent, was unilaterally injected in the medial forebrain bundle of rats. As early as 18 h after the injection a rapid decrease in TH-mRNA level was observed in the substantia nigra and the ventral tegmental area (SN/VTA) on the injected side. In contrast, TH protein levels remained stable for 48 h, and decreased later in both cells bodies and terminals (caudate/putamen). The number of TH-immunopositive cells in SN/VTA increased after colchicine equally in both sides, excluding a neurotoxic effect. These results suggest that TH gene expression is controlled by a retrogradely transported activating factor rather than by feedback inhibition by the end product, i.e. TH protein.
Frain
O
O
Institut Alfred Fessard, CNRS, Gif sur Yvette, France.
Leviel
V
V
D000818:Animals; D001370:Axonal Transport / Q000187:drug effects / Q000502:physiology*; D001369:Axons / Q000187:drug effects / Q000502:physiology*; D002421:Caudate Nucleus / Q000201:enzymology; D003078:Colchicine / Q000494:pharmacology*; D007839:Functional Laterality; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D008297:Male; D008636:Mesencephalon / Q000201:enzymology* / Q000502:physiology; D009411:Nerve Endings / Q000201:enzymology; D009474:Neurons / Q000187:drug effects / Q000201:enzymology*; D011699:Putamen / Q000201:enzymology; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D013378:Substantia Nigra / Q000187:drug effects / Q000201:enzymology; D013681:Tegmentum Mesencephali / Q000187:drug effects / Q000201:enzymology; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects; D014446:Tyrosine 3-Monooxygenase / Q000096:biosynthesis*
D012333:RNA, Messenger; D014446:Tyrosine 3-Monooxygenase; D003078:Colchicine