抄録
The squid giant axon was found to change its diameter by about 1 nm upon electrical stimulation. An increasing phase was followed by a decreasing phase in a few milliseconds. This response was shown to be associated with a 1 mPa change in intracellular pressure (increase in diameter with increase in pressure). Both responses could be enhanced by Ca2+ and suppressed by tetrodotoxin applied externally. They became large after removal of the axoplasm. Under the voltage clamp condition, the pressure response appeared in a potential dependent manner. The potential dependence was parabolic, indicating that electrostriction is involved in the mechanical response. Application of a K+-rich solution or a lidocaine containing solution suppressed the response induced by voltage clamp pulses. These findings suggested that the thickness of the membrane in the phospholipid part changes as the potential changes. These mechanical responses may have some roles in determining the kinetics of ionic channels.
