Summary
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1.
Voltage-clamped nodes of Ranvier of frog nerve fibres were subjected to 2-sec depolarizing impulses at a rate of 0.2 sec−1.
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2.
On application of veratridine an inward current component was observed during the pulses and inward current tails appeared on repolarization.
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3.
The growing amplitude of these tails was a measure of the drug effect which developed in two phases with time constants, τon and τ′ on, of 3.3 to 4.0 sec and 35 to 77 sec, respectively (between 45 and 1.5 μM veratridine at room temperature).
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4.
Washout, too, proceeded in two phases with time constants, τoff and τ′ off, of about 4.5 and 78 sec (both in 15 and 45 μM veratridine).
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5.
After a prolonged treatment the alkaloid effect was only partially reversible, but a first fast washout phase was always observed.
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6.
The rate of veratrinization appeared to be independent of membrane potential.
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This work was supported by the Deutsche Forschungsgemeinschaft.
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Ulbricht, W. Rate of veratridine action on the nodal membrane. Pflugers Arch. 336, 201–212 (1972). https://doi.org/10.1007/BF00590044
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DOI: https://doi.org/10.1007/BF00590044