Effects of tyrosine kinase inhibitors on voltage-dependent Ba(2+) currents in the guinea-pig gastric antrum.
We have investigated whether tyrosine kinases modify the activity of voltage-dependent Ba(2+) currents (I(Ba)) recorded from guinea-pig gastric myocytes by use of patch-clamp techniques. All experiments were carried on single smooth muscle cells, dispersed from the circular layer of the guinea-pig gastric antrum. Genistein ( > or = 10 microM), a specific tyrosine kinase inhibitor, reduced the peak amplitude of I(Ba) in a voltage- and concentration-dependent manner. Daidzein ( > or = 30 microM), an inactive analog of genistein, also inhibited I(Ba) in a concentration-dependent manner. Similarly, other types of tyrosine kinase inhibitors (lavendustin A and tyrphostin 23) suppressed the peak amplitude of I(Ba) in a concentration-dependent manner. These results indicate that tyrosine kinases may be essential to regulate Ca(2+) mobilization through voltage-dependent Ca(2+) channels in gastric myocytes.
Zhu
H-L
HL
Department of Pharmacology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Ito
Y
Y
Teramoto
N
N
D000818:Animals; D001464:Barium; D015220:Calcium Channels / Q000502:physiology*; D019833:Genistein / Q000494:pharmacology; D006168:Guinea Pigs; D007473:Ion Channels / Q000187:drug effects*; D008564:Membrane Potentials / Q000187:drug effects; D032389:Myocytes, Smooth Muscle / Q000502:physiology*; D018408:Patch-Clamp Techniques; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011706:Pyloric Antrum / Q000166:cytology / Q000201:enzymology
D015220:Calcium Channels; D007473:Ion Channels; D047428:Protein Kinase Inhibitors; D001464:Barium; D019833:Genistein; D011505:Protein-Tyrosine Kinases