ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Abstract: Using tritium-labelled 4,5,6,7-tetrahydroisoxazolo[4,5-c]pyridin-3-ol (THPO) its tissue distribution and metabolism were investigated in adult mice and 4-day-old chicks after systemic administration of the drug. It was found not to be significantly metabolized in the brain since metabolites of THPO corresponding to only approximately 8% of the parent compound could be detected 30 min after administration of the drug intramuscularly in mice. In the liver, however, THPO was found to be metabolized to a considerable extent. In chicks THPO metabolites were found in the brain but they accounted for 〈 35% of the radioactivity. The brain concentration of THPO in mice and chicks corresponded to respectively 10 and 50% of the dose injected intramuscularly and the tissue level was essentially constant for at least 3 h after injection. Following systemic administration of THPO to mice and chicks the contents of aspartate, glutamate, glutamine, and γ-aminobutyric acid (GABA) in whole brain and in synaptosomes was determined. It was found that only GABA contents were affected being increased in synaptosomes from mice and decreased in whole brain in chicks. Doses of THPO. which in chicks but not in mice led to brain levels that were sufficient to inhibit glial GABA uptake, were found to protect chicks but not mice against isonicotinic acid hydrazide-induced seizures. The findings are compatible with the notion that THPO exerts its anticonvulsant activity by inhibition of astrocytic GABA uptake. Key Words: 4,5,6.7-Tetrahydroisoxazolo[4,5-c]pyridin-3-ol (THPO)—Anticonvulsant—γ-Aminobutyric acid—Mice—Chicks—THPO metabolism. Schousboe A. et al. Tissue distribution, metabolism, anticonvulsant efficacy, and effect on brain amino acid levels of the glia-selective 7-aminobutyric acid transport inhibitor 4,5,6,7-tetrahydroisoxazolo[4,5-c]pyridin-3-ol in mice and chicks. J. Neurochem. 47, 758–763 (1986).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1471-4159.1986.tb00676.x
