The Tohoku Journal of Experimental Medicine

The abnormalities of the lung structure and function in the senile and emphysema lung were studied, and the cardinal factors of the development from the senile lung to chronic obstructive emphysema were speculated as follows.
First, the chronic bronchitis which is the common disorder in senile lung, apt to develop bronchiolitis, with acinus inflammation in the acute exacerbation and causes the damage of the wall of respiratory bronchioli and alveolar ducts. Secondly, as the result, the pressure unbalance between the intrapulmonary pressure which tends to collapse airway, the elasticity which tends to distend airway and the intrabronchial pressure develops. These agents which disturb the pressure balance were studied theoretically and measured practically. Thirdly, the check valve phenomenon develops by the pressure unbalance. The viscious circle repeating check valve phenomenon accelerates the progression of the chronic pulmonary emphysema. The other agents; obstructive change, cough, exercise and hyperventilation also accerelate the development and progression of the chronic pulmonary emphysema. We believe the above theory is the most important factor in the pathogenesis of the chronic pulmonary emphysema.
The new index of check valve index (C. V. I.) was proposed in differentiating chronic pulmonary emphysema from bronchial asthma. Application of check valve index in conjuction with one second vital capacity per vital capacity (1''VC/VC) is available for diagnosis of chronic pulmonary emphysema.

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1) The property of the motor end-plate was studied by recording the end-plate potential (e. p. p.) and the end-plate current (e. p. c.) by means of the intracellular microelectrode method and by measuring the equilibrium potential for the e. p. p. in Na-lack and Cl-lack (Cl ions are replaced with NO₃, SO₄, and I ions) Ringer solution. The e. p. c. measured by the voltage-clamp method in the end-plate region is the current required to keep the membrane potential at the resting level during the neuromuscular transmission and represents the temporal change of the shunting resistance across the membrane potential.
2) The time course of the e. p. c. when compared with that of the e. p. p. showed a characteristic difference. Experiments were made to prove whether a potential similar to the e. p. p. can be reconstructed at the membrane if the shunting resistance is changed according to the time course of the e. p. c. The calculations were made using an analog computor on an electrically equivalent circuit of the end-plate region. The time course of the computed e. p. p.'s under various conditions were similar to that of the natural e. p. p.'s. The relationship between the magnitude of the e. p. p. and the intensity of the e. p. c., and the time course between them under various curarine concentration were discussed.
3) When the membrane potentials under the clamped condition were shifted at various levels for 200 msec and indirect stimulations were applied the relationships between the membrane currents at the e. p. c.'s were obtained. The effective resistance of the resting membrane calculated from those relationship was 200-600KΩ. A straight line connecting the peak amplitude of the e. p. c.'s plotted against various clamped voltages of the membrane crossed the abscissa at 50 to 80 mV, while the resting potential was usually -70 to -90 mV. Thus the equilibrium potential for the e.p.p. was -10 to -30 mV of the membrane potential, and the minimum value of the shunting resistance across the membrane potential in the end-plate region, calculated from the tangents formed by these relation-ships, was 600KΩ to 2MΩ under minimum curarized conditions.
4) When the external Na ions were replaced by sucrose-Ringer solution, the e. p. p. and the e. p. c. were sometimes reversed. The equilibrium potential in Na-lack solution shifted near to the normal resting potential and the resting potential went up towards zero by 20 to 30 mV. The mechanism for the production of the reversed e. p. p. and the reversed e. p. c. were discussed from these two potential levels, and it was concluded that the same mechanism produces the inhibitory synaptic potential obitaned from other tissues.
5) The effects of various anions, such as NO₃, SO₄, and I, on the e. p. p. and the e. p. c. were investigated. The resistance of the resting membrane was increased by about twice by full replacement of Ringer solution with Cl-lack solution. The amplitude of the e. p. p. was enlarged by NO₃, but not by SO₄, . From the relationships between the magnitude of the e. p. p.'s and the intensity of e. p. c.'s in sucrose and NO₃, solution, it was clear that the amplitude of e. p. p. in NO₃, increased without an increase of the intensity of the e. p. c. Thus the increase of the e. p. p. in NO₃, solution is due to the resistance increase of the resting membrane.

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