Shifts in calcium in ischemic and reperfused rat hearts: a cytochemical and morphometric study of the effects of diltiazem.
Effects of diltiazem upon mitochondrial ultrastructure and distribution of calcium were studied following ischemia (27 minutes) and reperfusion (30 minutes). Hearts receiving no drug recovered low contractile function, while mitochondria nearly doubled in cross-sectional area (0.98 vs 0.56 micron 2) and were structurally damaged (1.88 vs 0.17 score). Mitochondria contained fine calcium deposits (0.029-micron diam) in mildly damaged cells, larger deposits in moderately damaged cells, and a large deposit (0.17-0.29-micron diam) in severely injured cells. Glycocalyx Ca2+ stain, observed in nonischemic hearts, was reduced in moderately and severely damaged cells. Increased mitochondrial Ca2+ may be associated with loss of glycocalyx Ca2+. Diltiazem (7.5 microns), added before ischemia, improved recovery of contractile function and prevented mitochondrial swelling, structural grade change, and increase in mitochondrial Ca2+. Reduction in mitochondrial Ca2+ stain by diltiazem was associated with the maintenance of normal glycocalyx Ca2+.
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Department of Biology, University of North Carolina, Charlotte 28223.
Watts
J A
JA
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004110:Diltiazem / Q000627:therapeutic use*; D008929:Mitochondria, Heart / Q000187:drug effects* / Q000378:metabolism; D009200:Myocardial Contraction / Q000502:physiology; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control*; D009206:Myocardium / Q000737:chemistry / Q000648:ultrastructure*; D051381:Rats; D011919:Rats, Inbred Strains
D004110:Diltiazem; D002118:Calcium