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. 1990 Apr;57(4):903–909. doi: 10.1016/S0006-3495(90)82610-2

Single delayed rectifier channels in frog atrial cells. Effects of beta-adrenergic stimulation.

I Duchatelle-Gourdon 1, H C Hartzell 1
PMCID: PMC1280791  PMID: 2160847

Abstract

The patch-clamp technique with two pipettes was used to record single delayed K+ channels (cell-attached electrode) and to control the potential and the composition of the intracellular compartment (whole-cell electrode). With 30 microM cAMP in the cell and physiological potassium concentrations inside and outside the patch, a channel carrying an outward current was characterized. Its open probability was very low and the channel was recorded in only 5% of patches under control conditions. Increasing intracellular cAMP increased the probability of finding a channel in a patch 10-fold. The channel had the characteristics expected of a delayed rectifier channel. The time-course of its ensemble average resembled the whole-cell current in the same cell. The current-voltage relationship exhibited inward rectification, with a slope conductance of 20 pS in the linear portion and a reversal potential close to EK. Both the open- and the closed-time distributions were described by the sum of two exponentials, suggesting a complicated gating scheme involving two closed states and two open states. The beta-adrenergic stimulation did not change the conductance of the channel, but increased its probability of opening.

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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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