title: Electrophysiological study on the high K+ sensitivity of rat glomerulosa cells.
abstract: Elevation of extracellular potassium concentration by as little as some tenth of mM activates rat adrenal glomerulosa cells. In the present study some factors responsible for this high K+ sensitivity were examined. Using whole-cell voltage-clamp technique we found that both T-type and L-type voltage-dependent Ca2+ channels have very low threshold potential (-71 and -58 mV, resp.). By means of patch-clamp technique combined with single-cell fluorimetry we also provided evidence that the activation of Igl, a K+-activated inward rectifying current is associated with Ca2+ influx. Both the low activation threshold of voltage-dependent Ca2+ channels and the function of Igl contribute to the exceptional K+ sensitivity of the glomerulosa cells.
authors.affiliation: Department of Physiology and Laboratory of Cellular and Molecular Physiology, Semmelweis University of Medicine, H-1444 Budapest, P.O. Box 259, Hungary.
authors.forename: P
authors.initials: P
authors.lastname: Várnai
authors.forename: G L
authors.initials: GL
authors.lastname: Petheö
authors.forename: J K
authors.initials: JK
authors.lastname: Makara
authors.forename: A
authors.initials: A
authors.lastname: Spät
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D004553:Electric Conductivity; D004594:Electrophysiology; D005470:Fluorometry; D008564:Membrane Potentials; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction; D015384:Zona Glomerulosa / Q000187:drug effects* / Q000502:physiology*
chemical_list: D015220:Calcium Channels; D011188:Potassium; D002118:Calcium