A study of a K~+ channel in the basolateral membrane of renal proximal tubule recorded from single rat nephron in vitro / 第三军医大学学报

ABSTRACT

Objective To study the physiological properties of a potassium channel in the basolateral membrane (BLM) of proximal tubule. Methods Nephrons were dissected from rat kidney under a stereoscopic microscope. The standard configuration for single channel tight seal patch clamp technique was used to record channel currents from the BLM. Results A kind of potassium channel with low conductance and inward rectification was easily recorded in the BLM of the proximal tubule. The channel current occurred spontaneously in 81% seals made on the BLM. In the patches, with no spontaneous channel activity, the channel current occurred when the pressure increased. In the inside out configuration, run down was present in channel activity. The open dwelling time constants of the potassium channel were 0.524 ms and 5.087 ms, while the closed dwelling time constants were 1.029 ms and 16.500 ms. Conclusion A type of potassium channels with low conductance, stretch sensibility and chemistry sensibility, presenting kinetic properties as two opening and two closing states, are widely distributed in the basolateral membrane of proximal tubule.