The manner of metabolism is different between the atrium and the ventricle

Energy of the cardiac muscle largely depends on fatty acid oxidation (FAO). It is known that the atrium and the ventricle have tissue‐specific functions, structures, gene expressions, and pathologies. The ventricle pumps blood and its muscle wall is thicker than atrial wall. Thus, energy utilization should be different between them. However a tissue‐specific pattern of cardiac metabolism remains incompletely understood. Recently, innovative techniques have enabled comprehensive analysis of metabolites. Therefore, we aimed to clarify differences between the atrium and the ventricle and used male C57B6 mice at the age of 6 weeks to comprehensively measure metabolites of their atria and ventricles by capillary electrophoresis and mass spectrometry. We found that the metabolic pattern was significantly different between them. The levels of lactate, acetyl CoA, and succinate in the ventricles were higher than the atrium. Moreover, N‐acetyl aspartate (NAA) and acetylcholine were higher in the atrium than the ventricles. Our data suggest that energy metabolism of the ventricle is more active than the atrium and depends on not only FAO but also glycolysis with lactate fermentation, whereas that of the atrium largely depends on FAO. Furthermore, the atrium is innervated and NAA might be a molecular marker of it. We hope these findings contribute to better understanding of tissue‐specific characters and pathologies.