Effects of blocking the dopamine biosynthesis and of neurotoxic dopamine depletion with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on voluntary wheel running in mice.
In Parkinson's disease (PD) compensatory mechanisms such as an increase of the de novo biosynthesis of dopamine (DA) are thought to delay the onset of motor impairment. Here, we investigated whether the tyrosine hydroxylase (TH) inhibitor alpha-methyl-para-tyrosine (AMPT) affects behavioral deficits in the running wheel activity induced by the selective dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Immediately after MPTP treatment C57bl/6 mice showed reduced running wheel activity which lasted during the entire active phase (20:00 to 08:00 h), recovered to baseline levels in the following 2 days and remained stable up to the end of the experiment. AMPT challenge significantly reduced wheel running activity in MPTP-treated mice in the first 3 h after treatment. Post mortem HPLC analysis detected mean striatal DA levels in saline + saline and saline + AMPT-treated mice of 14.32 and 9.83 ng/mg, respectively and in MPTP + saline and MPTP + AMPT-treated mice of 1.73 and 0.69 ng/mg, respectively. Taken together, de novo biosynthesis of DA is a crucial component of the compensatory mechanisms which contributes to masking long-term behavioral deficits in the MPTP mouse model. Additionally, wheel running activity might provide a useful tool to study MPTP-induced behavioral deficits, shifts in circadian rhythmicity, and further compensatory mechanisms relevant to PD.
Leng
Andreas
A
Laboratory of Behavioural Neurobiology, Swiss Federal Institute of Technology Zurich, Schorenstrasse 16, CH-8603 Schwerzenbach, Switzerland.
Mura
Anna
A
Hengerer
Bastian
B
Feldon
Joram
J
Ferger
Boris
B
D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine / Q000494:pharmacology*; D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D004195:Disease Models, Animal; D004298:Dopamine / Q000096:biosynthesis / Q000172:deficiency*; D050483:Dopamine Plasma Membrane Transport Proteins; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D006719:Homovanillic Acid / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D009043:Motor Activity / Q000187:drug effects*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D012420:Running; D013997:Time Factors; D014446:Tyrosine 3-Monooxygenase / Q000037:antagonists & inhibitors*; D019805:alpha-Methyltyrosine / Q000494:pharmacology*
D050483:Dopamine Plasma Membrane Transport Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D015102:3,4-Dihydroxyphenylacetic Acid; D019805:alpha-Methyltyrosine; D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; D014446:Tyrosine 3-Monooxygenase; D004298:Dopamine; D006719:Homovanillic Acid