BS3 Chemical Crosslinking Assay: Evaluating the Effect of Chronic Stress on Cell Surface GABAA Receptor Presentation in the Rodent Brain

Anxiety is a state of emotion that variably affects animal behaviors, including cognitive functions. Behavioral signs of anxiety are observed across the animal kingdom and can be recognized as either adaptive or maladaptive responses to a wide range of stress modalities. Rodents provide a proven experimental model for translational studies addressing the integrative mechanisms of anxiety at the molecular, cellular, and circuit levels. In particular, the chronic psychosocial stress paradigm elicits maladaptive responses mimicking anxiety-/depressive-like behavioral phenotypes that are analogous between humans and rodents. While previous studies show significant effects of chronic stress on neurotransmitter contents in the brain, the effect of stress on neurotransmitter receptor levels is understudied. In this article, we present an experimental method to quantitate the neuronal surface levels of neurotransmitter receptors in mice under chronic stress, especially focusing on gamma-aminobutyric acid (GABA) receptors, which are implicated in the regulation of emotion and cognition. Using the membrane-impermeable irreversible chemical crosslinker, bissulfosuccinimidyl suberate (BS3), we show that chronic stress significantly downregulates the surface availability of GABA(A) receptors in the prefrontal cortex. The neuronal surface levels of GABA(A) receptors are the rate-limiting process for GABA neurotransmission and could, therefore, be used as a molecular marker or a proxy of the degree of anxiety-/depressive-like phenotypes in experimental animal models. This crosslinking approach is applicable to a variety of receptor systems for neurotransmitters or neuromodulators expressed in any brain region and is expected to contribute to a deeper understanding of the mechanisms underlying emotion and cognition.

Automated summary

Anxiety is a state of emotion that affects animal behaviors, and rodents provide a good model for studying its mechanisms. This article introduces an experimental method to measure the surface levels of neurotransmitter receptors under chronic stress in mice, specifically focusing on GABA receptors. The study shows that chronic stress decreases the availability of GABA(A) receptors in the prefrontal cortex. This method can be applied to various receptor systems in different brain regions and will contribute to a better understanding of emotion and cognition mechanisms.