title: Calcium channel current in cultured rat mesangial cells.
abstract: The presence of voltage-dependent calcium channels has been suggested in mesangial cells by using calcium-sensitive fluorescent probes. However, direct electrophysiological evidence for voltage-dependent calcium channels has not yet been presented. In this study voltage-dependent calcium channels were studied in cultured rat mesangial cells. Whole-cell patch-clamp experiments were done with 50 mM Ba2+ as a charge carrier. Step depolarizing pulses from a holding potential of -50 mV produced an inward barium current at potentials more positive than -10 mV, and a peak current (10-45 pA) was obtained at a membrane potential of approximately +30 mV. The inward current was augmented by 100 nM Bay K 8644, attenuated by 1 microM nifedipine, and abolished by 50 microM Cd2+. These results indicate that the inward current is a barium current flowing through L-type calcium channels. This may be the first study that demonstrates the presence of L-type calcium channels in mesangial cells.
authors.affiliation: Department of Pharmacology, Fukui Medical School, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Nishio
authors.forename: H
authors.initials: H
authors.lastname: Tsukahara
authors.forename: M
authors.initials: M
authors.lastname: Hiraoka
authors.forename: M
authors.initials: M
authors.lastname: Sudo
authors.forename: S
authors.initials: S
authors.lastname: Kigoshi
authors.forename: I
authors.initials: I
authors.lastname: Muramatsu
mesh_terms: D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000818:Animals; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D005920:Glomerular Mesangium / Q000378:metabolism*; D008297:Male; D008564:Membrane Potentials; D009543:Nifedipine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D015220:Calcium Channels; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D009543:Nifedipine