The effects of diltiazem (2.2 x 10-7 and 2.2 x 10-6 N) on isometric contraction and K+-induced contracture (Pc) were determined for right ventricular muscles from normal cats and cats with right ventricular systolic hypertension (RVSH) monitored 4-15 days after partial pulmonary artery obstruction Muscles obtained from cats with RVSH had significantly decreased maximum isometric force (Po) and maximum rate of force development (dF/dt). Diltiazem (2.2 x 10-7 and 2.2 x 10-6 M) significantly reduced Pc of both normal and pressure-overloaded muscle. Po of normal muscle was decreased only by 2.2 x 10-6 M, while Po of pressure-overloaded muscle was significantly reduced at a lower concentration (2.2 x 10-7 M). The effect of diltiazem was reversed by ↑ [Ca2+]0. These results demonstrate that contractile function of pressure-overloaded ventricular myocardium is more sensitive to diltiazem.
|Original language||English (US)|
|Number of pages||9|
|Journal||Archives Internationales de Pharmacodynamie et de Therapie|
|State||Published - Jun 4 1982|
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