eng Oriental Scientific Publishing Company Biomedical and Pharmacology Journal 0974-6242 2020-03-28 13 1 325 333 10.13005/bpj/1892 31106 article Inoyat Jumayev 1 Pulat Usmanov 1 Shavkat Rustamov 1 Sherzod Zhurakulov 2 Institute of Biophysics and Biochemistry, National University of Uzbekistan, Tashkent, Uzbekistan. Institute of Chemistry of Plant Substances, Uzbek Academy of Sciences, Tashkent, Uzbekistan. In this study, mechanisms of inotropic action of some isoquinoline alkaloids 1-(4-dimethylaminophenyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline (F-24), 1-(2-chloro-4,5-methylenedioxyphenyl)-2-hydroxyethyl-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline (N-14) and 1-(2-сhloro-4,5-methylenedioxyphenyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline (F-14) were studied. The F-24, F-14, and N-14 alkaloids have been shown to have a negative effect on papillary muscle contraction activity, IC₅₀ value -16,8 µM, 14,03 µM and 12 µM. Са²⁺_L-channel blocker - nifedipine, adenylate cyclase (AС) activator–forskolin, β-adrenoreceptor (β-AR) blocker – propranolol, protein kinase С (PKС) activator – phorbol 12-myristate 13-acetate and SR RyR2 activator caffeine were used. Inotropic effects of F-24, F-14 and N-14 isoquinoline alkaloids on cardiomyocytes were suggested, based on results obtained in experiments carried in cardiomyocytes β-AR → [cAMP] → PKA → [Са²⁺]_in ↑ cascade, PKC, RyR2 and Na⁺/Ca²⁺ modulation. https://biomedpharmajournal.org/vol13no1/comparative-inotropic-effects-of-the-some-isoquinoline-alkaloids/ Inotropic Effect Isoquinoline Alkaloids Papillary Muscle