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Abstract

In the following, an attempt will be made to discuss the role of the K⁺ conductive pathway in the nephron. The aim of Table 1 is to give a systematic summary of what is known about K⁺-conductive pathways along the nephron. This table provides references to pertinent experimental work. In addition, this table clearly documents that a K⁺ conductive pathway is present in most, if not all cells of the different nephron segments; its functional role, however, may be quite different. Rather than giving a systematic overview, the present text seeks to provide new insights into the functional role of the K⁺-conductive pathways in several segments of the nephron. After an introduction into the two most important methods to examine the conductive properties of the nephron, namely the use of intracellular microelectrodes and the patch clamp technique, we shall focus on three issues: 1) the need for K⁺ recycling across the basolateral membrane in proximal tubule segments; 2) the specific role of the apical K⁺-conductance in the diluting segment as a means to recycle K⁺; and 3) the role of the apical K⁺-conductance in the collecting tubule for net K⁺ secretion.