Mikroskopisch-elektrophysiologische Untersuchung des Internodiums der markhaltigen Nervenfaser unter Einwirkung von Saponin und Elektrolyten

Abstract

The effects of various substances upon the myelin sheath of a nerve fibre have been examined by recording the action current through the myelin sheath as well as by taking its microphotographs at the same time. — (1) Saponine remarkably increased the current through the myelin sheath and prolonged the conduction time until the conduction of impulses failed. Conspicuous changes in the structure of the myelin sheath and axoplasm were observed, which is in good agreement with the electrical changes. The electrical changes could be interpreted as due to the decrease of the axon resistance by gradual penetration of saponine. — (2) KOH, NH₄Cl, concentrated NaCl and KCl affected the myelin very slowly compared with saponine, but they increased the myelin current relative to the nodal current. The structural changes were quite different from those due to saponine. — (3) Several other electrolytes, even in very high concentrations, showed little effect upon the electrical properties of the intemodal fibre, although marked structural changes were noticed.