Surface morphology of Purkinje cells and myocardial cells following chemical digestion

Abstract

From light and transmission electron microscopic studies, it has been long known that Purkinje cells of mammalian hearts have morphological characteristics different from ordinary myocardial cells. In the present study, not only Purkinje cells and myocardial cells but also connective tissue sheaths surrounding these cells were investigated by combined scanning electron microscopy(SEM) and chemical digestion.The moderator band of adult sheep heart was used because it possessed both Purkinje cells and myocardial cells (Fig.1). Tissue blocks were immersed in Karnovsky’s fixative for 3hr or longer. Some fixed tissues were inrrtersed in a 3-5% aqueous solution of NaClO for 1 min to digest the endocardial endothelium, and then were treated with 8N HCl for 30 min at 60°C to remove connection tissue elements. The others were iirmersed in a 2N NaOH or KOH solution for 7 days at room temperature to digest cellular elements. After freeze-cracking in a 40% dimethyl sulfoxide solution, the tissues were washed throughout in a saline solution containing tween 20, placed in a 1% aqueous solution of tannic acid for 2hr and conductive-stained with 1% OsO4 for 2hr.