Valium Research Today is a free monthly online journal that collates and summarizes the latest research about Valium, including details on diazepam, depression, side-effects, withdrawal.

Anticonvulsant and anxiolytic-like effects of compounds isolated from Polygala sabulosa (Polygalaceae) in rodents: in vitro and in vivo interactions with benzodiazepine binding sites.

Duarte FS, Marder M, Hoeller AA, Duzzioni M, Mendes BG, Pizzolatti MG, De Lima TC

Laboratory of Neuropharmacology - Department of Pharmacology, Federal University of Santa Catarina, Florianópolis, SC, Brazil.

RATIONALE: Polygala sabulosa, a folk medicine, presents dihydrostyryl-2-pyrones (DST) and styryl-2-pyrones (STY), compounds structurally similar to kavalactones. Our previous study showed that the ethyl acetate fraction (EA) and these constituents present anxiolytic-like, hypno-sedative, and anticonvulsant effects in mice. OBJECTIVES: This study investigated the role of benzodiazepine binding site (BDZ-bs) in the central effects of either EA or three DST (1, 2, and 3) and three STY (4, 5, and 7), using in vivo and in vitro assays. METHODS AND RESULTS: In the elevated plus-maze (EPM), flumazenil (FMZ), a BDZ antagonist, partially blocked the anxiolytic-like effect of DST-3 or STY-4 and STY-7, but not DST-1. Using electroencephalogram (EEG), EA protected against pentylenetetrazole (PTZ)-induced convulsion in rats, an effect partially blocked by FMZ, suggesting the participation of the BDZ-bs in this action. EA also protected against the maximal electroshock (MES)-induced convulsions in mice, a profile distinct from diazepam (DZP). DST and STY compounds inhibited the [(3)H]-flunitrazepam ([(3)H]-FNZ) binding to BDZ-bs in rat cortical synaptosomes with K (i) higher than 100 muM (DST-1), 41.7 muM (DST-2), 35.8 muM (DST-3), 90.3 muM (STY-4), 31.0 muM (STY-5) and 70.0 muM (STY-7). In the saturation assay, DST-3 and STY-7 competitively inhibited the binding of [(3)H]-FNZ to BDZ-bs with a significant decrease in apparent affinity (K (d)) and no change in maximal binding (B (max)). CONCLUSIONS: The present data support a partial BDZ-bs mediation of the anxiolytic-like and anticonvulsant effects of EA of P. sabulosa and its main isolated constituents, DST and STY.

Published 21 March 2008 in Psychopharmacology (Berl), 197(3): 351-60.
Full-text of this article is available online (may require subscription).

© 2004-2008 Valium Research Today. All Rights Reserved.