Antisense oligonucleotide against the Ca channel beta subunit decreases L-type Ca current in rat ventricular myocytes.
The role of endogenous beta subunits of the L-type Ca channel in native cardiac ventricular myocytes is unclear. We have therefore investigated the effect of inhibiting beta subunit expression in rat myocytes, by culturing isolated myocytes for 24 h with either antisense oligonucleotide against the beta subunit or with scrambled oligonucleotide (control). Alpha1 subunit expression and distribution were then determined by immunolabeling, and L-type Ca current measured using the whole cell patch-clamp technique. Cells treated with antisense showed increased perinuclear staining for alpha1, decreased Ca current amplitude and a small rightward shift of the activation curve and the I-V relation, with no significant effect on inactivation. These data suggest that endogenous beta subunits in native cardiac myocytes help to traffic the alpha1 subunit to the cell membrane and thus play a major role in determining Ca current amplitude.
Leach
Rob N
RN
Institute of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK.
Brette
Fabien
F
Orchard
Clive H
CH
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020746:Calcium Channels, L-Type / Q000502:physiology*; D020013:Calcium Signaling / Q000502:physiology*; D002478:Cells, Cultured; D020868:Gene Silencing / Q000502:physiology; D006352:Heart Ventricles / Q000166:cytology; D008297:Male; D008564:Membrane Potentials / Q000502:physiology; D032383:Myocytes, Cardiac / Q000502:physiology*; D016376:Oligonucleotides, Antisense / Q000008:administration & dosage / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D016276:Ventricular Function
D020746:Calcium Channels, L-Type; D016376:Oligonucleotides, Antisense; D002118:Calcium