New Insights Into Pharmacology of GABAA Receptor Alpha Subunits-Selective Modulators.

Background: Benzodiazepines have long held a leading position in medical therapeutics, known for their multiple common therapeutic properties and primarily being prescribed for anxiety and insomnia. However, their lack of specificity and various side effects have led to a reevaluation of their long-term use, resulting in a rapid growth in the literature focusing on targeted therapies.

Areas of uncertainty: Despite many efforts, uncertainties persist and there are heterogeneous findings across studies regarding the pharmacological effects attributed to gamma-aminobutyric acid type A (GABAA) receptor subunits. Selective compounds targeting GABAA receptor alpha subunits are currently under active research and definitive conclusions have not been reached yet. Some compounds have not progressed to clinical trials, while others, if advanced, have been halted. These challenges emphasize the difficulty in translating preclinical findings into clinical use.

Data sources: A literature review was conducted using the PubMed database, searching for articles discussing GABAA receptor subunits. The search was refined by including only selective compounds with potential anxiolytic and cognitive enhancement properties.

Results: Findings reveal compounds with promising anxiolytic and antidepressant effects with minimal sedation and absence of tolerance development. Moreover, some compounds show potential in alleviating cognitive dysfunction. There is a broad spectrum of potential therapeutic applications for selective compounds, ranging from neurological disorders such as epilepsy and neuropathic pain to cognitive dysfunction-related conditions. Currently, the leading selective compounds with the most promising results in ongoing clinical trials are basmisanil and darigabat. Basmisanil holds further exploration potential in the treatment of cognitive impairment and related conditions, while darigabat shows progress in the advancement of adjunctive therapy of focal onset seizures and for the treatment of panic disorder, respectively.

Conclusions: Future drug discovery efforts are encouraged to focus on positive allosteric modulators that selectively target the α2, α3 subunits and negative/positive allosteric modulators that target the α5 subunit of the GABAA receptor. The pursuit of ligands possessing only anxiolytic effects or those enhancing cognition continues to be an important focus for future research, with promising advancements depicted in recent studies.