| Abstrakt: |
A single dose of orally administered DL-a-methyltyrosine methylester hydrochloride (AMT) significantly increased the number of errors made by cats performing a spatial delayed response (DR) task. The same doses of AMT had no such effect on simultaneous visual discrimination (VD) performance. Response latencies were increased in all cats, whichever task performed. In an attempt to correlate the behavioral and biochemical effects of AMT, dopamine (DA), noradrenaline (NA) and serotonin (5-HT) were assayed in 5 brain structures, 4 to 48 h after 100 to 175 mg/kg. DA was reduced significantly with all doses of AMT used, NA with doses of 125 mg/kg and more. 5-HT increased significantly after 100 and 125 mg/kg but remained unchanged after higher doses. Due to the simultaneous action of AMT on DA, NA and 5-HT, the respective roles of these amines are difficult to dissociate. In contradistinction, previous findings suggest that brain DA be responsible for the impairment of DR performance. |
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