ETA and ETB Receptor are isoforms of endothelin receptor. The ETA receptors on vascular smooth muscle cells mediate vasoconstriction. Otherwise, ETB Receptor is present in both endothelial and vascular smooth muscle cells. Besides, ETB receptor mediates the release of NO and prostanoids from endothelial cell. In addition, Endothelin is a vasoconstrictor endothelium-derived peptide. Endothelin has three isoforms called endothelin-1 (ET-1), endothelin-2 (ET-2), and endothelin-3 (ET-3). Importantly, Endothelin acts on ETA and ETB receptors. Therefore, BQ3020, an ET-1 analog and the ETB receptor agonist, has great potential in cardiovascular disease research.

BQ-3020 is a potent and selective ETB receptor agonist, and produce bladder neck smooth muscle relaxation.

In vitro, BQ-3020 displaces [125I] ET-1 binding to ETB receptor with an IC50 value of 0.2 nM. Besides, BQ-3020 can produce bladder neck smooth muscle relaxation. BQ-3020 elicits vasoconstriction in the rabbit pulmonary artery. BQ-3020 (0.01-300 nM, 7 min), produces concentration-dependent relaxations on PhE-precontracted urothelium-denuded strips. Similarly, BQ-3020 (0.01-00 nM, 20 min) also causes potent dose-dependent vasoconstriction with an EC50 value of 0.57 nM in rabbit pulmonary arteries.

Moreover, BQ-3020 attenuates cancer pain in vivo. Specifically, in mice with squamous cell carcinoma (SCC) induced pain model, BQ-3020 (3 mg/kg for intratumor administration, single dose) attenuates cancer pain by approximately 50% up to 3 hours post-injection compared to PBS-vehicle and contralateral injection. In this model, BQ-3020 increases paw withdrawal thresholds compared to the control group.

Above all, BQ-3020 is a selective and potent ETB receptor agonist. BQ-3020 produces bladder neck smooth muscle relaxation. BQ-3020 also relieves pain in squamous cell carcinoma (SCC). BQ-3020 can be used for cardiovascular disease research.


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