[Changes of calcium transport capacity of myocardium and myocardial mitochondria during sepsis].

On the isolated perfused heart model of septic rats, the present study showed that: (1) Calcium content and 45Ca-influx of myocardium increased 190%, 208% (P < 0.01) and that of mitochondria elevated 332%, 178% (P < 0.01) respectively with no change of myocardial 45Ca-release during sepsis. (2) 10(-8) mol/L calcitonin gene-related peptide (CGRP) or 10(-7) mol/L atriopeptin (ANP) added into the Krebs-Henseleit solution could effectively reduce 45Ca-influx to myocardium and mitochondria with no effect on myocardial 45Ca-release. (3) The calcium uptake reserve of mitochondria evaluated in vitro showed that the maximal calcium uptake and uptake velocity of mitochondria during sepsis were reduced 34.6%, 33.3% (P < 0.01) respectively. The data suggested that the net increase of myocardial Ca2+ content resulted from increase of 45Ca-influx with no change of 45Ca-efflux and the reduction of mitochondrial Ca2+ buffering capacity during sepsis were key events in the pathogenesis of intracellular Ca(2+)-overload. CGRP and ANP could effectively alleviate Ca(2+)-overload of myocardium and mitochondria. This may have some cellular protection action during sepsis.