Evidence for the Existence of the Inositol Tris/Tetrakisphosphate Pathway in Rat Heart
In skeletal and cardiac muscles, polyphosphoinositide hydrolysis by phospholipase C is increased by electrical or hormonal stimulation, thus producing inositol-1,4,5-trisphosphate (Ins-1,4,5-P3) and diacylglycerol (Vergaraet al., 1985; Poggioliet al., 1986). Ins-1,4,5-P3was shown to release Ca2+ from sarcoplasmic reticulum and promote tension in skinned fibers (Hirataet al., 1984; Noseket al., 1986; Movsesianet al., 1985). Diglycerides activate protein kinase C., which in turn may influence certain ionic permeabilities (De Riemeret al., 1985) and the sensitivity of myofilaments to Ca2+ (Endoh and Blinks, 1988).
KeywordsSarcoplasmic Reticulum Inositol Phosphate Inositol Trisphosphate RINm5F Cell Phosphomonoesterase Activity
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