Effect of bradykinin on cultured bovine corneal endothelial cells.
OBJECTIVE
To clarify the effect of bradykinin on cytosolic free calcium mobilization and cell proliferation in cultured bovine corneal endothelial cells (BCEC).


METHODS
The cytosolic free calcium concentration (Ca2+]i) was measured with the InCa(TM) Imaging System after the treatment of bradykinin (10(-11) to 10(-7) M) alone or with the pretreatments of EGTA, bradykinin receptor (Bk1 and Bk2) antagonists and an inhibition of phospholipase C (U-73122). Also, the effect of bradykinin on cell proliferation in BCEC was evaluated using cell counts.


RESULTS
In BCEC, [Ca2+]i in the resting state was 87 +/- 9 nM. Bradykinin induced an increment of [Ca2+]i in a concentration-dependent manner and its 50% effective concentration was approximately 5 x 10(-11) M. A [Ca2+]i increment at 10(-8) M bradykinin was inhibited with the pretreatment of EGTA, an extracellular calcium chelator. U-73122 (5 x 10(-6) M) attenuated the bradykinin-induced [Ca2+]i increment. The pretreatment of HOE-140 (Bk2 antagonist) almost attenuated the bradykinin (10(-8) M)-induced [Ca2+]i increase, but des-Arg9-[Leu(8)]-bradykinin (Bk1 antagonist) did not suppress it. To investigate the physiological effect of bradykinin, the effect of bradykinin on cell proliferation was studied. 10(-8) M of bradykinin produced a significant increase in cell numbers. This mitogenic effect of bradykinin was inhibited by the Bk2 antagonist.


CONCLUSIONS
Bradykinin-induced stimulation of the signal transduction pathway in BCEC is coupled with the Bk2 type receptor. Furthermore, bradykinin produces the mitogenic effect in BCEC.
Yang
S W
SW
Department of Ophthalmology, College of Medicine, Catholic University of Korea, Seoul, Korea.
Lee
W K
WK
Lee
E J
EJ
Kim
K Y
KY
Lim
Y
Y
Lee
K H
KH
Rha
H K
HK
Hahn
T W
TW
D000818:Animals; D001920:Bradykinin / Q000031:analogs & derivatives / Q000494:pharmacology*; D065168:Bradykinin Receptor Antagonists; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D002452:Cell Count; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004533:Egtazic Acid / Q000494:pharmacology; D004728:Endothelium, Corneal / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004963:Estrenes / Q000494:pharmacology; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D011760:Pyrrolidinones / Q000494:pharmacology; D043782:Receptor, Bradykinin B2; D018002:Receptors, Bradykinin / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000378:metabolism
D065168:Bradykinin Receptor Antagonists; D004963:Estrenes; D011760:Pyrrolidinones; D043782:Receptor, Bradykinin B2; D018002:Receptors, Bradykinin; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D004533:Egtazic Acid; C065679:icatibant; D015544:Inositol 1,4,5-Trisphosphate; D010738:Type C Phospholipases; D001920:Bradykinin; D002118:Calcium