Striatal dopaminergic fiber recovery after acute L-DOPA treatment in 6-hydroxydopamine (6-OHDA) lesioned rats.
In order to examine the acute effects of L: -DOPA treatment following 6-hydroxydopamine (6-OHDA) injection into rat medial forebrain bundle (MFB). Sprague-Dawley rats (n = 48) received either 6-OHDA, via intracranial unilateral injection, into the MFB (experimental group) or saline 0.9% (control group). Administration of L: -DOPA or saline 0.9% began 1 month after the 6-OHDA injection for 10 consecutive days. Within 3 days, an increase in the density of striatal tyrosine hydroxylase (TH) immunoreactive fibers within the striatum, when compared to the control group was observed. There was no difference in the loss of substantia nigra pars compacta (SNpc) dopaminergic (DA) neurons between. The greater density of TH fibers in the striatum following L: -DOPA may be related to recovery of the DA phenotype and/or sprouting of TH axon terminals. Only animals with severe cell loss in the SNpc experienced abnormal involuntary movements (AIMs) or "dyskinesias" in response to L: -DOPA, which did not correlate with striatal TH fiber density, suggesting that induction of TH-positive fibers does not contribute to the occurrence of dyskinesia. The relationship between cell loss, fiber density and AIM to the abundance of markers of microglial activation were also examined. Iba-1, a microglial marker, immunoreactivity was not affected by L: -DOPA treatment, was not correlated with the severity of AIM indicating that microglial activation does not contribute to dyskinetic phenomena.
Fang
Chuanqin
C
Department of Neurology, Daping Hospital, Third Military Medical University, Chongqing 400042, China.
Yin
Jinbo
J
Xu
Zhiqiang
Z
Wang
Yanjiang
Y
Xu
Haiwei
H
Zhou
Huadong
H
Gao
Changyue
C
D000818:Animals; D000978:Antiparkinson Agents / Q000494:pharmacology*; D004195:Disease Models, Animal; D004298:Dopamine / Q000378:metabolism*; D004409:Dyskinesia, Drug-Induced / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D005260:Female; D007980:Levodopa / Q000494:pharmacology*; D008474:Medial Forebrain Bundle / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009412:Nerve Fibers / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D016627:Oxidopamine; D020734:Parkinsonian Disorders / Q000139:chemically induced / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013378:Substantia Nigra / Q000187:drug effects / Q000378:metabolism / Q000473:pathology
D000978:Antiparkinson Agents; D007980:Levodopa; D016627:Oxidopamine; D004298:Dopamine