Calyculin A increases voltage-dependent inward current in smooth muscle cells isolated from guinea pig taenia coli.
The effects of a potent phosphatase inhibitor, calyculin A (CL-A), on inward currents in guinea pig taenia coli smooth muscle cells were examined. CL-A increased the inward current, and this effect of CL-A was inhibited by a protein kinase C inhibitor, H-7, and by nifedipine. Phorbol 12,13-dibutyrate, an activator of protein kinase C, also increased the inward current and this effect was antagonized by H-7. These results suggest that in guinea pig taenia coli smooth muscle cells CL-A may facilitate the opening of the L-type Ca2+ channels through the protein kinase C-dependent phosphorylation system.
Usuki
T
T
Department of Physiology, Sapporo Medical College, Japan.
Obara
K
K
Someya
T
T
Ozaki
H
H
Karaki
H
H
Fusetani
N
N
Yabu
H
H
D000818:Animals; D001464:Barium / Q000502:physiology; D015220:Calcium Channels / Q000187:drug effects* / Q000502:physiology; D002469:Cell Separation; D003106:Colon; D006168:Guinea Pigs; D008387:Marine Toxins; D008564:Membrane Potentials / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D010080:Oxazoles / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors
D015220:Calcium Channels; D008387:Marine Toxins; D010080:Oxazoles; D001464:Barium; C059041:calyculin A; D011493:Protein Kinase C