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. 1970 Apr;10(4):323–344. doi: 10.1016/S0006-3495(70)86305-6

The Hyperpolarizing Region of the Current-Voltage Curve in Frog Skin

Oscar A Candia
PMCID: PMC1367757  PMID: 5436882

Abstract

Excitability (action potential and refractory period) has been described by A. Finkelstein in the depolarizing region of the current-voltage (I-V) curve of the isolated frog skin. Recently Fishman and Macey interpreted this phenomenon as a consequence of a region with negative resistance that confers to the I-V curve an N shape. We have studied the I-V relation of the isolated frog skin in the hyperpolarizing region with a current-ramp system. It was found that in Na2SO4 Ringer's, the resistance continuously increases in the hyperpolarizing direction. When hyperpolarization reaches 300 mv an electrical breakdown occurs, occasionally followed by a region of negative resistance. In NaCl Ringer's the breakdown was also found although the I-V relation was reasonably linear. Unidirectional Na+ outflux was measured at different levels of voltage clamping across the skin and with different Na+ concentrations in the solutions. The Na+ outflux was found to be relatively independent of these parameters. Based on these results a Na+ rectifying structure is postulated. An electrical model for active Na+ transport including a diode and an oscillator is proposed. The effects of CO2, nitrogen, amiloride, and ouabain on the I-V relation are described.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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