Membrane potential and cation channels in rat juxtaglomerular cells

• Published in: Acta physiologica Scandinavica Vol. 181; no. 4; pp. 391 - 396
• Main Authors: Friis, U. G., Jørgensen, F., Andreasen, D., Jensen, B. L., Skøtt, O.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01-08-2004; Blackwell Science
• Subjects: Animals; Biological and medical sciences; calcium channels; Calcium Channels - physiology; cAMP; Cyclic AMP - physiology; Fundamental and applied biological sciences. Psychology; Juxtaglomerular Apparatus - cytology; Juxtaglomerular Apparatus - physiology; juxtaglomerular cells; Membrane Potentials - physiology; potassium channels; Potassium Channels, Calcium-Activated - physiology; Rats; renin release; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Calcium; Rat; calcium channels; renin release; Electrophysiology; Ionic channel; cAMP; Inorganic element; Kidney; Renin; potassium channels; Aspartic endopeptidases; Membrane potential; Membrane channel; Release; Enzyme; Rodentia; Cyclic AMP; juxtaglomerular cells; Peptidases; Vertebrata; Mammalia; Urinary system; Hydrolases; Cations; Juxtaglomerular apparatus; Potassium
• ISSN: 0001-6772; 1365-201X
• DOI: 10.1111/j.1365-201X.2004.01310.x

The relationship between membrane potential and cation channels in juxtaglomerular (JG) cells is not well understood. Here we review electrophysiological and molecular studies of JG cells demonstrating the presence of large voltage‐sensitive, calcium‐activated potassium channels (BKCa) of the ZERO splice variant, which is also activated by cAMP. These channels explain the hyperpolarization, which has been observed after stimulation of renin release with cAMP. In addition, there is now evidence that JG cells express functional L‐type voltage‐dependent calcium channels (Cav 1.2), which in situations with strong depolarization lead to calcium influx and inhibition of renin release. In most in vivo situations the membrane potential is probably protected against depolarization by the BKCa channels.