Some factors affecting the concentrations of para-hydroxyphenylacetic acid and meta-hydroxyphenylacetic acid in the mouse caudate nucleus
✍ Scribed by P. S. McQuade; Dr. A. V. Juorio
- Publisher
- John Wiley and Sons
- Year
- 1983
- Tongue
- English
- Weight
- 548 KB
- Volume
- 10
- Category
- Article
- ISSN
- 0360-4012
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✦ Synopsis
Acid hydrolysis of mouse caudate homogenates results in a significantly increased concentration of para-hydroxyphenylacetic acid @-HPAA). Thus p-HPAA appears to be significantly present as an acid-labile conjugate in the niouse caudate nucleus. Saline injection also increased the concentration of the acid metabolite of the tyramines.
The subcutaneous injection of either metu-hydroxyphenylacetic acid (m-HPAA) or p-HPAA or both produccd at 0.5 hr and 2.0 hr largc increascs in the mouse caudate nucleus concentrations of m-and/or p-HPAA. Similarly at 2.0 hr the injection of a combination of puru-and mera-tyramine caused large increases in the acid metabolite concentrations.
Probenecid, at a dose of 500 mgikg, increased striatal p-HPAA and m-HPAA concentrations. Probenecid, injected prior to the administration of p-HPAA and m-HPAA, did not reduce the increased concentrations of these two acid metabolites previously observed after the administration of the acid metabolites alone. It thus appears that p-HPAA and mHPAA are transportcd from the brain by a probenecid-sensitive mechanism, but in the presence of high blood concentrations, p-HPAA and m-HPAA may enter the brain by a mechanism that is not affected by probenecid.