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OBJECTIVE To explore the possible mechanisms underlying the positive inotropic effect of MCI-154. METHODS Skinned fibers with disrupted or preserved sarcoplasmic reticulum (SR) were prepared by saponin 500 or 50 mg.L-1. The tension-pCa relationship and pCa50 of saponin (500 mg.L-1)-skinned fibers were taken as the indices of Ca2+ sensitivity of contractile proteins. The amplitude of caffeine-induced contracture was an index of Ca2+ release from SR in saponin (50 mg.L-1)-skinned fibers. RESULTS 1) MCI-154 (0.1 mmol.L-1) showed a Ca2+ sensitizing effect on contractile proteins. The pCa50 was increased to 5.84 (5.54-6.14) compared with control value 5.54 (5.30-5.79) (P < 0.01, n = 8). Hill coefficient n was decreased by 0.29 (P < 0.01, n = 8); 2) No contracture was produced by MCI-154 in preparations with preserved SR. Caffeine-induced contracture before and after MCI-154 treatment were not changed (P > 0.05, n = 4). CONCLUSIONS MCI-154 directly enhances the Ca2+ sensitivity of contractile protein but has little effect on Ca2+ release from SR in rat skinned cardiac fibers.
Y Huang, and
Z H He, and
Y X Li
June 1989,
European journal of pharmacology,
Y Huang, and
Z H He, and
Y X Li
September 1999,
Zhongguo yao li xue bao = Acta pharmacologica Sinica,
Y Huang, and
Z H He, and
Y X Li
September 2000,
Acta pharmacologica Sinica,
Y Huang, and
Z H He, and
Y X Li
January 1990,
Biochemical pharmacology,
Y Huang, and
Z H He, and
Y X Li
April 1986,
Cell calcium,
Y Huang, and
Z H He, and
Y X Li
October 1970,
Nature,
Y Huang, and
Z H He, and
Y X Li
February 1996,
The Journal of physiology,
Y Huang, and
Z H He, and
Y X Li
June 1996,
The Journal of physiology,
Y Huang, and
Z H He, and
Y X Li
January 1993,
Basic research in cardiology,
Y Huang, and
Z H He, and
Y X Li
March 1993,
The American journal of physiology,
