Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10958415 | Neurochemistry International | 2005 | 12 Pages |
Abstract
The effects of acute and chronic administration of the serotonin (5-HT)1B agonist CP-93,129, on 5-HT synthesis rates were evaluated using the α-[14C]methyl-l-tryptophan (α-MTrp) autoradiographic method. In the acute treatment study, CP-93,129 (7 mg/kg) was injected intraperitoneally 30 min before the α-MTrp injection (30 μCi over 2 min). A single dose of CP-93,129 caused a significant increase in the synthesis in the median raphe nucleus (MR) without a significant influence on the dorsal raphe nucleus (DR). There was a reduction in 5-HT synthesis in almost all of the projection areas. In the chronic treatment study, CP-93,129 was administered continuously (7 mg/kg/day) for 14 days using an osmotic minipump implanted subcutaneously. The chronic treatment with CP-93,129 did not produce a significant change in 5-HT synthesis in the raphe nuclei nor in the nerve terminal structures, except for the medial frontal bundle and the visual and sensory-motor cortices. The unaltered 5-HT synthesis rates in the chronic treatment study probably reflect a normalization of the synthesis as a result of the desensitization of 5-HT1B autoreceptors and/or heteroreceptors.
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Authors
Shu Hasegawa, Arata Watanabe, Kyoko Nishi, Khanh Q. Nguyen, Mirko Diksic,