Biophysical Journal 9: 127-139 (1969)
© 1969 the Biophysical Society

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Fishman, H. M. Articles by Macey, R. I. Search for Related Content PubMed PubMed Citation Articles by Fishman, H. M. Articles by Macey, R. I.

The N-Shaped Current-Potential Characteristic in Frog Skin

I. Time Development during Step Voltage Clamp

ABSTRACT

A fast (10 µsec) voltage-clamp system similar to that used on nerve axons was applied across the frog skin. An electrical analog is used to obtain the electrical parameters and to estimate the time (300 µsec) required to voltage clamp the excitable membrane layer in the skin. The speed of the clamp allows observation of the early development in time of an N-shaped current-potential (I-V) relation. The isochronal I-V curves constructed from step clamp data show the beginning of a negative slope in about 250 µsec after successively applied step changes in skin potential (> 200 mv). Subsequently, the negative slope reaches a quasi-steady state interval (0.4-1.5 msec) and then decays and disappears in the next 20 msec. The negative slope I-V characteristic is only found in skins which exhibit spike generation under current clamp.