Enhancing effect of taurine in the rat caudate spindle. II. Effect of bilateral 6-hydroxydopamine lesions of the nigro-striatal dopamine system.
Bilateral injections of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle of rats resulted in destruction of dopamine (DA) nerve terminals in the striatum. DA contents decreased to 16.8, 15.0 and 13.7% of control values on 3, 5 and 7 days after the lesions, respectively. The time course of the effect of 6-OHDA lesions on apomorphine (0.5 mg/kg, IV)-induced stereotypy was investigated as the index of the development of supersensitivity. Stereotypy was unchanged on 3 days, but was enhanced 5 and 7 days after 6-OHDA lesions. Therefore, the sensitivity of postsynaptic DA receptors for apomorphine did not change 3 days after 6-OHDA lesions, although the striatal DA was depleted. The effects of bilateral injections of taurine into the striatum on the rat caudate spindle were determined 3 days after 6-OHDA lesions. Taurine, at a dose of 30 micrograms, enhanced the spindle in sham-operated rats, but this enhancement was not seen after 6-OHDA lesions. Intravenous administration of apomorphine (0.5 mg/kg) to lesioned rats suppressed the spindle, and this effect was prevented by a lower dose (3 micrograms) of taurine. These results provide further evidence that taurine enhances the spindle, possibly by decreasing the activity of the nigro-striatal DA system at the pre- and postsynaptic sites.
Hashimoto-Kitsukawa
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S
Research Center, Taisho Pharmaceutical Co., Ltd., Saitama, Japan.
Okuyama
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S
Aihara
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H
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001923:Brain Chemistry / Q000187:drug effects; D001930:Brain Injuries / Q000139:chemically induced* / Q000473:pathology; D002421:Caudate Nucleus / Q000187:drug effects*; D003342:Corpus Striatum / Q000187:drug effects; D004298:Dopamine / Q000032:analysis; D004569:Electroencephalography; D006892:Hydroxydopamines / Q000494:pharmacology*; D008297:Male; D009638:Norepinephrine / Q000032:analysis; D016627:Oxidopamine; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000032:analysis; D013654:Taurine / Q000494:pharmacology*; D013997:Time Factors
D006892:Hydroxydopamines; D013654:Taurine; D012701:Serotonin; D016627:Oxidopamine; D004298:Dopamine; D009638:Norepinephrine