Effects of paraquat on the substantia nigra of the wistar rats: neurochemical, histological, and behavioral studies.
Effects of paraquat on the substantia nigra of the male Wistar rats we re studied pharmacologically by a intracerebral injection of paraquat. The neurochemical, morphological, and behavioral changes observed after a unilateral intranigral injection of paraquat (1-5 microgram) were as follows: (1) neurochemically, paraquat caused dose-dependent depletion of dopamine in the ipsilateral striatum starting 2 weeks after treatment; this effect was long-lasting and irreversible. The ipsilateral striatal dopamine level in animals treated with 3 microgram paraquat was even decreased by 91.5%. (2) Morphologically, 2 microgram of paraquat produced marked loss of Nissl substances and prominent glial reaction in the substantia nigra, while 3 microgram of paraquat caused a severe loss of neurons. (3) Behaviorally, paraquat caused a vigorous rotational behavior in rats contralateral to the lesioned side in response to apomorphine administration (0.5 mg/kg, sc). This effect was dose-dependent and lasted for the entire 16-week experimental period. Taken together, these data indicate that intranigrally injected paraquat may possess marked neurotoxicity and induce degeneration of the rat nigrostriatal dopaminergic system.
Liou
H H
HH
Department of Neurology, National Taiwan University, Taipei, Republic of China.
Chen
R C
RC
Tsai
Y F
YF
Chen
W P
WP
Chang
Y C
YC
Tsai
M C
MC
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006540:Herbicides / Q000008:administration & dosage / Q000633:toxicity*; D007276:Injections, Intraventricular; D008297:Male; D009562:Nissl Bodies / Q000473:pathology; D010269:Paraquat / Q000008:administration & dosage / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D012399:Rotation; D013239:Stereotyped Behavior / Q000187:drug effects; D013378:Substantia Nigra / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology
D006540:Herbicides; D001058:Apomorphine; D010269:Paraquat; D004298:Dopamine