Intracellular mechanisms of @entity1855 and XXXX action on striated muscle of the @entity95 .

@entity1855 @entity95 @entity5834 @entity2701 @entity3988 @entity460 @entity1159 @entity141
Skinned fibers from striated muscle were used to study the intracellular mechanisms (contractile proteins and sarcoplasmic reticulum [SR]) of action of @entity3988 (DT) and @entity1855 (VP) on muscle contraction. @entity95 papillary muscle (PM), and the skeletal muscles adductor magnus (AM, fast-twitch) and soleus (SL, slow-twitch) were used. The muscles were skinned by homogenization and fibre bundles for PM and single fibres for AM and SL were dissected from the homogenate and mounted on photodiode force transducers. VP (0.1-3.0 mmol/l) (and to a lesser degree DT) increased @entity141 -activated @entity2701 development of the contractile protains in PM and SL and decreased it in AM (+[4-20]%, +4%, -[14-28]%, respectively). Both drugs increased the submaximal @entity141 -activated @entity2701 development at the order of PM = SL greater than AM in a dose-dependent manner. The changes of half-maximal pCa50 at 1 mmol/l VP were 0.25, 0.25, and 0.15, respectively. For @entity141 uptake and release from the SR, VP as well as DT (0.1-3.0 mmol/l) in the uptake phase decreased @entity5834 -induced @entity2701 transients in a dose-dependent fashion. At 0.01-3.0 mmol/l, the drugs directly induced @entity141 release from the SR or enhanced @entity5834 -induced @entity2701 transients with the exception that in PM, DT attenuated @entity5834 -induced @entity2701 transients. Thus, VP and DT have similar intracellular mechanisms of action in striated muscle. Both drugs induced @entity460 release from the SR and increase @entity141 sensitivity of the contractile proteins, and thus could be the underlying mechanisms for potentiating twitch @entity2701 , and inducing @entity1159 .
