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In vitro study of the interaction of Tilia europeae L. aqueous extract with GABA A receptors in rat brain
Author(s) -
Cavadas C.,
Fontes Ribeiro C. A.,
Santos M. S.,
Cunha A. P.,
Macedo T.,
Caramona M. M.,
Cotrim M. D.
Publication year - 1997
Publication title -
phytotherapy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 129
eISSN - 1099-1573
pISSN - 0951-418X
DOI - 10.1002/(sici)1099-1573(199702)11:1<17::aid-ptr948>3.0.co;2-6
Subject(s) - muscimol , flunitrazepam , gabaa receptor , chemistry , pharmacology , receptor , binding site , benzodiazepine , in vitro , biochemistry , biology
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 ‐ to synaptoneurosomes from cortices. The extract inhibited [ 3 H]muscimol binding, stimulated 36 ClCl ‐ 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 μ 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. © 1997 John Wiley & Sons, Ltd.