ABSTRACT
Electron microscopic autoradiographic investigations to study the localization of Ca in muscle were performed using heart muscle. The distribution of autoradiographic grains, originating from Ca-45 were compared above myofibrils and interfibrillar spaces of the ventricle, auricle and sinus node of the heart. Our aim was to get new data on the role of Ca in the mechanical activity of muscle with special consideration of the Ca content of interfibrillar spaces. The different distribution of grains in the muscle fibrils and interfibrillar spaces of various parts of the heart can be in connection with the different activities of these parts. The more Ca content in myofibrils of ventricle cells may be in connection with its greater mechanical activity and its work.
Subject(s)
Calcium/analysis , Myocardium/analysis , Animals , Autoradiography , Heart Atria/analysis , Heart Ventricles/analysis , Myocardium/ultrastructure , Myofibrils/analysis , Rana esculenta , Sarcoplasmic Reticulum/analysis , Sinoatrial Node/analysisABSTRACT
Electron microscopic autoradiographic investigations have been made to study the localization of Ca in the muscle the contraction of which was broken by soak in 99.8 per cent heavy water. The distribution of autoradiographic grains, originating from Ca-45 ingested by previous incubation, above longitudinal sections of these muscles were compared to the distribution of grains above muscles not treated in heavy water. Considerable difference in grain density was found above the A- and I-bands of the two different kinds of muscle and above their sarcoplasmic reticulum. The investigations concerning the sarcoplasmic reticulum were completed by the study of distribution of autoradiographic grains above the transversal sections of these muscles.
