Evidence that concentrations of ouabain which induce positive inotropic effects on the perfused guinea-pig heart increase the amount of calcium in a rapidly-exchangeable cellular compartment.

摘要: Abstract The effects of ouabain and adrenaline on kinetically distinct compartments exchangeable calcium associated with myocardial muscle cells were investigated using a Langendorff perfused guinea-pig heart preparation, 45 Ca 2+ outflow exchange technique, 51 Cr-EDTA to monitor the rate loss freely-diffusable from vascular interstitial spaces. A non-linear least squares curve-fitting procedure was used analyse data. minimum number required adequately describe each set data for five. These consisted freely-diffusible in spaces (monitored Cr-EDTA) three cells. concentration (0.15 μM), which enhanced force contraction by 60% without evidence toxicity, increased flux quantity space cellular compartment highest fractional transfer rate. Both decreased two lowest rates. results are consistent conclusion that one actions is increase rapidly-exchangeable bound extracellular sites sarcolemma and/or present myoplasm.