CGS-21680C

Alprazolam (Alp), a commonly used sleep medication in clinical practice, has several potential limitations, including a narrow therapeutic dosage range and a delayed sleep onset. CGS21680 (CGS), a selective agonist of the adenosine A_2A receptor, exhibits neuroinhibitory properties. This study aimed to evaluate the effects of CGS on the sleep properties of Alp. The sleep-inducing effects of Alp were assessed through the righting reflex, while the sedative effects of CGS were evaluated by spontaneous activity detection. The synergistic effect of CGS on Alp was evaluated by using electroencephalography and electromyography. The results indicate that we optimized and selected ED₅ dose of Alp and ED₅₀ dose of CGS for coadministration. CGS reduced the sleep latency induced by Alp and extended the sleep duration. The distribution of Alp in the brain was assessed through mass spectrometry imaging (MSI). The blood-brain barrier (BBB) model was established to evaluate the impact of CGS on the transmittance of Alp. The results indicated that CGS influenced the distribution of Alp across various brain regions and increased Alp's transmittance across the BBB. The metabolic pathways of GABA, glutamate, and glutamine were assessed through MSI and enzyme activity verification. The coadministration of Alp and CGS resulted in the regulation of GABA, glutamate, and glutamine during the sleep latency and sleep maintenance periods, respectively. In conclusion, the potentiating effect of CGS on the sleep-inducing properties of Alp is attributed to its ability to modulate the distribution of Alp in the brain by enhancing BBB permeability and its influence on Alp-induced neurotransmitter release.

Vascular inflammation and endothelial dysfunction secondary to unchecked activation of endothelium are key mechanisms underlying sepsis and organ failure. However, the intrinsic processes that mitigate excessive endothelial cell activation remain incompletely understood. To determine the central role of adenosine A2a receptor (A2aR) on macrophages in modulating lipopolysaccharide (LPS)‐induced vascular endothelial dysfunction, we constructed macrophage A2aR‐conditional knockout (Mac‐A2aR KO) mice, and stimulated the mice and macrophages with LPS. A2aR agonist, CGS21680, was administered to these models to further explore its impact. Results showed that knockout of Macrophage A2aR exacerbated LPS‐induced vascular permeability, oedema, inflammatory cardiac damage and upregulated expression of intercellular adhesion molecule‐1 (ICAM‐1) and E‐selectin in cardiopulmonary vascular endothelium. Moreover, deletion of A2aR on macrophages also markedly aggravated LPS‐induced increases in reactive oxygen species (ROS) and declines in antioxidant enzyme gene mRNA and protein expression levels related to oxidative stress (OS). Furthermore, deficiency of A2aR in bone marrow‐derived macrophages (BMDMs) promotes LPS‐induced macrophage M1 polarisation and secretion of inflammatory cytokines, especially tumour necrosis factor‐alpha (TNF‐α). Conversely, the pretreatment with CGS21680 in vivo and in vitro showed corresponding improvement in functions of vascular endothelial dysfunction. These data demonstrate that A2aR in macrophages represents a promising novel therapeutic target for LPS‐induced uncontrolled vascular endothelial injury and inflammation potentially through reducing macrophage M1 polarisation and OS and inhibiting the production and release of TNF‐α production.