In vitro study of the interaction of Tilia europeae L. aqueous extract with GABAA receptors in rat brain

✍ Scribed by C. Cavadas; C. A. Fontes Ribeiro; M. S. Santos; A. P. Cunha; T. Macedo; M. M. Caramona; M. D. Cotrim

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 120 KB
• Volume: 11
• Category: Article
• ISSN: 0951-418X
• DOI: 10.1002/(sici)1099-1573(199702)11:1<17::aid-ptr948>3.0.co;2-6

✦ Synopsis

The interaction of GABA A receptor-complex in rat brain was investigated in vitro with aqueous extracts obtained from the inflorescences of Tilia europeae L., using the [ 3 H]muscimol and [ 3 H]flunitrazepam binding techniques to synaptic membranes and the uptake of 36 Cl Ϫ to synaptoneurosomes from cortices. The extract inhibited [ 3 H]muscimol binding, stimulated 36 Cl Ϫ uptake by synaptoneurosomes and displaced at high concentrations, the [ 3 H]flunitrazepam bound to synaptic membranes. When analysed by HPLC, the aqueous extract of Tilia europeae L. contained several amino acids, including GABA (about 100 M). This GABA content can justify the displacement of [ 3 H]muscimol produced by the extract but it did not increase the binding of [ 3 H]flunitrazepam, as expected. Probably the extract contains other benzodiazepine-like substances which displace the [ 3 H]flunitrazepam binding and counteract the expected GABA-induced increase in [ 3 H]flunitrazepam binding.