Exploring the DS2 Scaffold for GABA_A Receptor Modulation: Progress toward the Development of a GABA_A δ-Subunit...

Area of Science:

• Neuroscience
• Pharmacology
• Molecular Biology

Background:

• Extrasynaptic delta-containing γ-aminobutyric acid type A receptors (GABA_ARs) are implicated in neurological disorders due to altered tonic inhibition.
• The compound DS2 is a known selective modulator of δ-GABA_ARs, serving as a valuable research tool.

Purpose of the Study:

• To synthesize and characterize novel DS2 analogues with modified pharmacological profiles.
• To identify compounds with selective negative allosteric modulation of δ-GABA_ARs.

Main Methods:

• Synthesis of DS2 analogues, including compound 1e with an N-methylated pyrrolyl ring.
• Electrophysiological evaluation of compound 1e on recombinant GABA_AR subtypes.
• Assessment of compound 1e's activity on receptors with gain-of-function mutations associated with neurological disorders.

Main Results:

• Compound 1e demonstrated negative allosteric modulation of δ-GABA_ARs, contrasting with DS2's positive modulation.
• 1e showed selectivity for δ-GABA_AR subtypes, with no activity at γ₂-containing subtypes.
• 1e effectively reduced GABA currents in receptors with mutations linked to neurodevelopmental disorders and epilepsy.

Conclusions:

• Compound 1e is a selective negative allosteric modulator of δ-GABA_ARs.
• 1e's brain permeability and ability to reduce excessive tonic inhibition make it a promising lead compound for neurological conditions.