Histochemical study of calmodulin in dog myocardial ischemia and sudden cardiac death.

The distribution of calmodulin was investigated in dog myocardium after coronary artery occlusion by an immunoperoxidase technic and compared with the distribution of myoglobin and the findings of hematoxylin-eosin (H-E) staining. After 60 min or more of coronary artery ligation, calmodulin diffused clearly from myocardium in the region of hypereosinophilia (H-E) or stained intensely in regions of a contraction band or hydropic appearance. Similar findings were observed in the myocardium of cases of sudden cardiac death. The intense staining for calmodulin would reflect the association of calmodulin with membranes in response to the calcium overload that plays an important role in myocardial injury. Calmodulin staining provided more information than myoglobin staining, which only detected diffusion from necrotic cells. This method would be useful to elucidate the implications of calcium and calmodulin during the development of myocardial injury.