THE EFFECT OF δ9-TETRAHYDROCANNABINOL (δ9-THC) ON THE TURNOVER RATE OF BRAIN SEROTONIN OF THE RAT |
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Authors: | D. A. Taylor M. R. Fennessy |
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Affiliation: | Department of Pharmacology, University of Melbourne, Victoria, Australia |
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Abstract: | 1. One isotopic and three non-isotopic methods were used to determine the effect of an acute intravenous dose of Δ9-tetrahydrocannabinol (Δ9-THC, 2 mg/kg) on the rat brain turnover rate of serotonin. 2. In control animals the turnover rate of serotonin was about 2 nmol/g per h. This rate was not altered by Δ9-THC when it was calculated from the rise of 5-hydroxyindoleacetic acid following probenecid or from the rise of serotonin following pargyline. 3. Δ9-THC did not alter the serotonin turnover rate when it was calculated from the conversion of 3H-tryptophan to 3H-serotonin. 4. The serotonin turnover rate was significantly increased by Δ9-THC when the rate was calculated from the decline of 5-hydroxyindoleacetic acid following pargyline. 5. These results suggest that Δ9-THC does not alter the turnover of rat brain serotonin. The previously reported Δ9-THC-induced changes in body temperature and increased brain levels of 5-hydroxyindoleacetic acid may be mediated by some other mechanism such as interference by Δ9-THC of the vesicular binding of serotonin. |
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Keywords: | Δ9-tetrahydrocannabinol serotonin turnover 5-hydroxyindoleacetic acid pargyline probenecid 3H-tryptophan |
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