GABA_A Receptor Modulators from the Chinese Herbal Drug Junci Medulla – The Pith of Juncus effusus

Abstract

The gamma-amino butyric acid (GABA) type A (GABA_A) receptor represents a crucial target for clinical agents in the treatment of anxiety and insomnia. Using the two-microelectrode voltage clamp technique on recombinant α ₁ β ₂ γ _2S GABA_A receptors, effusol (1) and dehydroeffusol (2) were isolated in a bioactivity-guided approach from the pith of Juncus effusus L. Both compounds concentration-dependently enhanced GABA induced chloride currents (I_GABA) by a maximum 188 ± 20 (1) and 239 ± 18 % (2), independent of the benzodiazepine (BZ) binding site. This activity on the GABA_A receptor may explain the traditional use of J. effusus as a sedative and anxiolytic agent in Chinese medicine.

Key words

Juncus effusus L. (Juncaceae) - GABA(A) receptor - voltage clamp - positive allosteric modulation - dehydroeffusol - effusol

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