Gαq-RGS2 loop activator modulates the activity of vario us agonists on isolated heart and aorta of normal rats

Abstract

The Gαq-RGS2 loop activator, 1-(5-chloro-2-hydroxyphenyl)-3-(4-(trifluoromethyl)-phenyl)-1H-1,2,4-triazol-5(4H)-one has demonstrated Gαq signaling inhibitor activity. Therefore, we aimed to study the effect of Gαq-RGS2 loop activator on isolated heart and aorta of normal rats. Heart and aorta were isolated from the sacrificed rats (n=6) and mounted on the langendroff's and organ bath assembly, respectively. The effect of various receptor-dependent (acetylcholine, angiotensin II and adrenaline) and independent (calcium chloride and sodium nitroprusside) agonists in absence and presence of Gαq-RGS2 loop activator on left ventricular systolic pressure (LVSP) and the contractile responseswere evaluated in isolated heart and aorta, respectively. Gαq-RGS2 loop activator (100 µM) significantly attenuated the adrenaline (p<0.001,) and angiotensin II (p<0.001) induced increase in LVSP in isolated heart and contractile response of adrenaline (p<0.01) and angiotensin II (p<0.01) in the aorta. However, effect calcium chloride did not significantly alter by Gαq-RGS2 loop activator. The effect of acetylcholinewas significantly (p<0.01, p<0.05) increased by Gαq-RGS2 loop activator in isolated heart and aorta. The effect of sodium nitroprusside significantly (p<0.01) potentiated by Gαq-RGS2 loop activator (100 µM) in isolated heart while it did not significantly alters in the aorta. Ultimately, the Gαq-RGS2 loop activator modulated the action of receptor-dependent agonists in isolated heart and aorta.