Cytomorphometric and biochemical differences between the muscle cells in atria and ventricles of the guinea pig heart

✍ Scribed by Plattner, H. ;Tiefenbrunner, F. ;Pfaller, W.

• Publisher: John Wiley and Sons
• Year: 1970
• Tongue: English
• Weight: 593 KB
• Volume: 167
• Category: Article
• ISSN: 0003-276X
• DOI: 10.1002/ar.1091670103

✦ Synopsis

Abstract

Differences in succinate dehydrogenase and cytochrome oxidase activity and also in the Q for a medium containing pyruvate, glutamate, fumarate and glucose (equimolar) were found using histochemical and manometrical methods, when muscle cells of the atria and the ventricles in the guinea pig heart were compared. Most of the activity values were higher in the ventricles than in the atria. According to cytomorphometric measurements, these differences can be explained by differences in the mitochondrial volume (per unit volume of cytoplasm) rather than by a different ultrastructural organization of the individual mitochondria, since they show the same stereological organization in both the atria and the ventricles. The reduced mitochondrial volume in the atria results in a lower density of “oxidative” (i.e., inner mitochondrial) membranes per unit volume of cytoplasm.