Monovalent currents through the T-type Cav3.1 channels and their block by Mg2+.
We have investigated the permeability of the Cav3.1 channel for Ca2+ and different monovalent cations and the block of the currents by Mg2+ ions. In the absence of extracellular divalent cations, the Cav3.1 channel was more permeable for Na+ than for Cs+ and impermeable for NMDG+. Monovalent currents were inhibited by Mg2+ of near physiological concentration by three orders of magnitude more effectively than the Ca2+ current. Inhibition of outward, but not inward current by Mg2+ was voltage-dependent. Furthermore, magnesium slowed down channel deactivation presumably by interacting with an open channel state.
Institute of Molecular Physiology and Genetics, Centre of Excellence for Cardiovascular Research, Slovak Academy of Sciences, Slovakia.
M
M
Kurejová
M
M
Pavlovicová
L'
L
Lacinová
D002118:Calcium / Q000378:metabolism*; D020747:Calcium Channels, T-Type / Q000187:drug effects / Q000502:physiology*; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology*; D007668:Kidney / Q000187:drug effects / Q000502:physiology*; D008274:Magnesium / Q000008:administration & dosage*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology*
C121855:CACNA1G protein, human; D020747:Calcium Channels, T-Type; D008274:Magnesium; D002118:Calcium