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The change in membrane capacitance and conductance of squid giant axons during hyper- and depolarizations was investigated. The measurements of capacitance and conductance were performed using an admittance bridge with resting, hyperpolarizaed and depolarized membranes. The duration of DC pulses is 20-40 msec and is long enough to permit the admittance(More)
The change in capacity of squid axon membrane during hyper- and depolarizations was investigated in the absence of ionic currents after the membrane was treated with pronase. In the presence of the inactivation process (h parameter), failure to observe the gating current in the frequency domain was attributed to the rapid attenuation of the possible(More)
  • S Takashima
  • 1985
The passive membrane capacitance and conductance of isolated single muscle fibers were investigated using a vaseline gap method. The results obtained with this method are consistent with those obtained using the microelectrode technique. It was confirmed that the membrane capacitance of skeletal muscle consisted of a large capacitance of tubular membrane(More)
Since the discovery of Cole and Curtis (1938. Nature (Lond.). 142:209 and 1939. J. Gen. Physiol. 22:649) that the imaginary components, i.e., capacitive and inductive components, of the admittance of squid axon membrane remained unchanged during the action potential, there have been numerous studies on impedance and admittance characteristics of nerves.(More)
The dipole moment of alamethicin, which produces voltage-dependent conductance in lipid-bilayer membranes, was measured in mixed solvents of ethanol and dioxane. The value of the dipole moment was found to increase from 40 to 75 DU (Debye units), as the concentration of ethanol increased from 0 (pure dioxane) to 40%. The relaxation frequency of alamethicin(More)
The high frequency dielectric constant of poly-adenine (poly-A) was measured between 1 MHz and 1 GHz. The purpose of these experiments was to investigate the state of water molecules that are bound to the charged groups of the poly-A molecule. Analysis of the data using the Maxwell's mixture equation revealed the dielectric constant of bound water higher(More)
The unique feature of the measurements of membrane capacitance and conductance of nerve axons is the facts that these measurements must be carried out in the presence of a bias potential (-60 mV) across the membrane and also that measurements are performed in the presence of time dependent and non-linear currents. The bias potential creates an electrical(More)
Passive electrical characteristics of perfused squid axon membrane are investigated. In a previous publication, we reported that the capacitance of intact squid axon membrane is partly frequency dependent. We extended the same measurement to perfused axons. We found that the electrical characteristics of perfused axon membrane are essentially the same as(More)