Learn More
The nonlinear membrane current-voltage relationship (I–V curve) for intact hyphae ofNeurospora crassa has been determined by means of a 3-electrode voltage-clamp technique, plus “quasi-linear” cable theory. Under normal conditions of growth and respiration, the membraneI–V curve is best described as a parabolic segement convex in the direction of(More)
Amiloride, present in the mucosal solution, causes the appearance of a distinct additional dispersion in the admittance spectrum of the apical membrane of toad urinary bladder. The parameters of this dispersion (characteristic frequency. amplitude) change with amiloride concentration and with membrane voltage. They allow the calculation of the overall rate(More)
The overall rate constants of blockage of apical Na channels by amiloride, previously determined by noise analysis, were obtained in macroscopic relaxation experiments with toad urinary bladders exposed to a mucosal Na activity of 60 mM. By the use of step voltage perturbations and by admittance analysis we show that the on-rate constant of blockage(More)
The current-voltage characteristics of the ATP-dependent proton pump in the plasma membrane of Neurospora have been explored under varied metabolic conditions imposed by mutation and by differential respiratory inhibition. The reversal potential, or presumed equilibrium potential, for the pump was observed at about -400 mV under energy-replete conditions,(More)
Exposing the apical membrane of toad urinary bladder to the ionophore nystatin lowers its resistance to less than 100 Ω cm2. The basolateral membrane can then be studied by means of transepithelial measurements. If the mucosal solution contains more than 5mm Na+, and serosal Na+ is substituted by K+, Cs+, or N-methyl-d-glucamine, the basolateral membrane(More)
Previous investigations of the frequency response of the action of light on the membrane potential inNitella have revealed 5 time constants and 3 zeros in the range of 2 sec to 20 min. Now, the frequency range is extended by means of filter and correlation techniques to its upper theoretical limit of about 20 Hz. Thus the number of experimentally accessible(More)
  • 1