EVALUATION OF THE EFFECTS OF ISOQUINOLINE ALKALOIDS F-4, F-43, AND F-45 ON CA2+ TRANSPORT SYSTEMS IN THE MEMBRANE OF AORTIC SMOOTH MUSCLE CELLS: IN VITRO EXPERIMENTS

This study investigates the dose-dependent effects of isoquinoline alkaloids F-4, F-43, and F-45 on the contractile activity of aortic muscle preparations induced by KCl (50 mM) and phenylephrine (1 µM). The results demonstrate that all tested compounds exhibit significant vasorelaxant activity. In KCl-induced contraction models, alkaloid F-45 showed the highest potency (IC50 = 32.9 µM, maximum inhibition of 84.0%), followed by F-43 (IC50 = 37.7 µM) and F-4 (IC50 = 42.1 µM). Further experiments using phenylephrine (PE) confirmed the alkaloids' influence on receptor-operated Ca2+ channels; specifically, alkaloid F-4 exhibited an IC50 of 12.5 µM with a maximum contraction reduction of 92.6%. The findings suggest that these isoquinoline alkaloids are promising candidates for the development of new vasodilatory agents to manage vascular tone and hypertension.