Bradykinin stimulates the intracellular calcium activity in human mesothelial cells.
OBJECTIVE
The aim of this study was to investigate the influence of bradykinin on the intracellular calcium activity ([Ca2+]i) in human mesothelial cells in culture.


RESULTS
Bradykinin (1-1000 nmol/l) caused a concentration-dependent and reversible increase of [Ca2+]i in mesothelial cells (n = 94); 10 nmol/l bradykinin increased [Ca2+]i from 23 +/- 9 to 670 +/- 170 nmol/l (n = 36). The pattern of the bradykinin-induced [Ca2+]i increase was biphasic with a transient [Ca2+]i peak, which was followed by a sustained [Ca2+]i plateau. The bradykinin-mediated [Ca2+]i plateau, but not the peak, was inhibited in a solution with an extracellular reduced Ca2+ concentration (from 1000 to 1 micromol/l, n = 11). Flufenamate (> or = 10 micromol/l), an inhibitor of non-selective ion channels abolished the bradykinin-mediated increase of [Ca2+], whereas the L-type Ca2+ channel blocker nicardipine (10 micromol/l) had no effect (n = 3-5). The [Ca2+]i response to bradykinin was inhibited by the BK2 antagonist Hoe 140 (IC50 +/- k7 nmol/l, n = 30).


CONCLUSIONS
The data indicate that bradykinin stimulates [Ca2+]i in mesothelial cells by a release of Ca2+ from intracellular stores and an influx from Ca2+ through non-selective channels via a BK2 receptor.
Department of Medicine, University of Freiburg, Germany.
M
M
Andre
S
S
Rahimi
P
P
Schollmeyer
H
H
Pavenstädt
D001920:Bradykinin / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000378:metabolism; D004848:Epithelium / Q000378:metabolism; D005110:Extracellular Space / Q000378:metabolism; D005439:Flufenamic Acid / Q000494:pharmacology; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism*; D009529:Nicardipine / Q000494:pharmacology; D009994:Osmolar Concentration; D010537:Peritoneum / Q000166:cytology / Q000378:metabolism*; D018002:Receptors, Bradykinin / Q000502:physiology
D002121:Calcium Channel Blockers; D018002:Receptors, Bradykinin; D005439:Flufenamic Acid; D009529:Nicardipine; D001920:Bradykinin; D002118:Calcium