ULTRASTRUCTURAL ALTERATIONS PRODUCED IN MAMMALIAN MYOCARDIUM BY VARIATION IN PERFUSATE IONIC COMPOSITION
ULTRASTRUCTURAL ALTERATIONS PRODUCED IN MAMMALIAN MYOCARDIUM BY VARIATION IN PERFUSATE IONIC COMPOSITION
复制标题
灌注液离子组成的变化导致哺乳动物心肌超微结构改变
作者：
M. Legato;D. Spiro;G. Langer
本研究描述了当灌流液中钠、钙和氯化物的浓度不同时，哺乳动物心肌亚细胞形态的变化。通过最近开发的一种灌流技术，用不同离子组成的等渗液对功能正常的犬乳头状肌进行灌流。对组织的电子显微镜检查显示，对照肌肉表现出令人满意的超微结构保存，表明该方案本身并未产生明显的形态假象。低氯化钠灌流引起横管和纵行肌浆网成分扩张。低钠或高钙浓度导致纵行肌浆网的管状成分扩张，而横管保持不变。高钙灌流引起线粒体肿胀和空泡化。观察到线粒体沉淀物有结晶的和无定形的，推测为单独的或与碳酸钙混合的磷酸钙。讨论了观察到的形态变化可能表明特定离子通透性的亚细胞位置的可能性。已知的钠离子和钙离子在哺乳动物心肌中的动力学行为与所产生的超微结构变化之间存在关联。
This study describes the changes produced in the subcellular morphology of mammalian myocardium when perfusate sodium, calcium, and chloride concentrations are varied. By means of a recently developed perfusion technique, functioning dog papillary muscles were perfused with isotonic solutions of varying ionic compositions. Examination of the tissue in the electron microscope revealed that control muscles showed satisfactory preservation of ultrastructure, demonstrating that the protocol itself did not create significant morphological artefact. Low sodium chloride perfusion produced dilatation of both transverse tubules and longitudinal sarcoplasmic reticulum elements. Low sodium or high calcium concentrations produced dilation of tubular elements of the longitudinal sarcoplasmic reticulum while leaving transverse tubules intact. High calcium perfusion produced mitochondrial swelling and vacuolization. Mitochondrial precipitate, both crystalline and amorphous in form, was observed and presumed to be calcium phosphate, either alone or mixed with calcium carbonate. The possibility that the morphological changes observed might indicate subcellular loci of specific ion permeability is discussed. A correlation of the known kinetic behavior of sodium and calcium ions in mammalian myocardium with the ultrastructural alterations produced is suggested.