Tyrosine phosphorylation is involved in Ca(2+)entry in human gingival fibroblasts.
Bradykinin (1 microM) and histamine (100 microM) evoked an initial transient increase and a subsequent sustained increase in intracellular Ca(2+) concentration ([Ca(2+)](i)) in fura-2-loaded human gingival fibroblasts, which may be attributed to Ca(2+) release from intracellular stores and Ca(2+) entry from extracellular sites, respectively. In fibroblasts pretreated with tyrosine kinase inhibitors such as herbimycin A (1 microM) and tyrphostin 47 (20 microM), the sustained level of [Ca(2+)](i) induced by bradykinin and histamine increased, but not the initial peak level. In the absence of external Ca(2+), bradykinin and histamine induced only the transient increase in [Ca(2+)](i), but a subsequent addition of Ca(2+) to the medium resulted in a sustained increase in [Ca(2+)](i) caused by Ca(2+)entry. Thapsigargin, an inhibitor of Ca(2+)-ATPase in inositol 1,4,5-trisphosphate-sensitive Ca(2+) stores, mimicked the effect of bradykinin and histamine. In the fibroblasts pretreated with tyrosine kinase inhibitors, the bradykinin-, histamine- and thapsigargin-induced Ca(2+) entry was clearly enhanced, but not the transient [Ca(2+)](i) increase. Tyrosine phosphatase inhibitor benzylphosphonic acid (200 microM) had no effect on Ca(2+)entry or transient [Ca(2+)](i) increase. These results suggest that tyrosine phosphorylation is involved in Ca(2+) entry in human gingival fibroblasts.
Ogata
Yorimasa
Y
Department of Periodontology, Nihon University School of Dentistry at Matsudo, Matsudo, 271-8587, Chiba, Japan. ogata@mascat.nihon-u.ac.jp
Nakao
Sumi
S
Shimizu
Emi
E
Matsuda-Honjyo
Yuko
Y
Yamazaki
Muneyoshi
M
Furuyama
Shunsuke
S
Sugiya
Hiroshi
H
D016227:Benzoquinones; D001920:Bradykinin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D015220:Calcium Channels / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D005881:Gingiva / Q000201:enzymology / Q000378:metabolism*; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D047029:Lactams, Macrocyclic; D010766:Phosphorylation / Q000187:drug effects; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011809:Quinones / Q000494:pharmacology; D011969:Receptors, Histamine H1 / Q000502:physiology; D017828:Rifabutin / Q000031:analogs & derivatives; D019284:Thapsigargin / Q000494:pharmacology; D013997:Time Factors; D014443:Tyrosine / Q000378:metabolism*; D020032:Tyrphostins / Q000494:pharmacology
D016227:Benzoquinones; D015220:Calcium Channels; D004791:Enzyme Inhibitors; D047029:Lactams, Macrocyclic; D011809:Quinones; D011969:Receptors, Histamine H1; D020032:Tyrphostins; C060152:tyrphostin 47; D017828:Rifabutin; D014443:Tyrosine; D019284:Thapsigargin; C020754:herbimycin; D006632:Histamine; D011505:Protein-Tyrosine Kinases; D001920:Bradykinin; D002118:Calcium