蛙皮膚の機械的刺激の生物物理的意義

On the biophysical aspects of mechanical stimulation to the frog skin

　皮膚に機械的刺激を加えた際，いかなる要素が特に有効にはたらくかを定めるため，パルス状の刺激と，直線的に漸増，漸減する波形を利用し，波形と反応の有無の間の関係を検討してみた。漸増刺激のPacini小体に対する効果^1），又猫の足蹠に対する効果^2）等については，既に報告されている。本論文では，蛙皮膚に対する刺激効果にもとづき，刺激の物理的性質を明かにするのが目的である。

　The excitability change of frog skin mecha-noreceptors were investigated by applying mechanical short pulses and or triangular pu-lses.

　1.When the absolute value of displacement is A and dA/dt=0, it causes changes of exci-tability, which was named mechanotonus. A rapid component of the pulse was effective in causing response of the receptor.

　2. The prefiring stages of supraliminal tri-angular pulses showed various time courses of excitability changes, but most of them in-dicated accommodation. In other words, the fall of threshold, expressed by the height of superposed pulses, was seen.

　3. In rising phase of the subliminal triangu-lar displacement, threshold expressed in amp-litude seemed to be lower than the one in falling phase.

　4. Velocity of displacements in mechanical stimuli was interpreted to be equivalent with electric current in electric stimulation of the excitable tissues.

　5. Strictly speaking, the threshold must be determined by the combination of velocity and duration of the mechanical displacement. At least, two factors are necessary to describe the threshold value.