Characterization of a b2-bradykinin receptor in human glomerular
podocytes.
Ardaillou, Nicole, V[acute]eronique Blaise, Karencostenbader, Yves
Vassitch, and Raymond Ardaillou.
INSERM U.64, H[circumflex]opital Tenon, Paris, France
APStracts 3:0099F, 1996.
We characterized bradykinin (BK) receptors in a human line of
glomerular visceral epithelial cells transfected by the SV40 virus
(hGVEC). [3H]-BK bound specifically in a manner consistent with a
single high-affinity site. Scatchard analysis yielded KD and Bmax
values of 0.28?+/- 0.04?nM and 76.6?+/- 4.9?fmol/mg, respectively.
Competition binding studies with selective BK type?2 (HOE?140)
receptor antagonist and type?1 (Des-Arg9-BK) receptor agonist showed
that hGVEC only expressed type?2 receptors, which was confirmed by
reverse transcription-polymerase chain reaction and ribonuclease
protection assay. BK stimulated intracellular calcium ion ([Ca2+]i)
release in a dose-dependent manner with a threshold at 1?nM. Hoe?140,
in contrast with DesArg9BK, abolished this effect. [Ca2+]i
stimulation was also inhibited by thapsigargin, an inhibitor of Ca2+
ATPase. EGTA attenuated but did not suppress the [Ca2+]i peak.These
results associated with the stimulatory effect of BK on inositol
phosphate production indicated that [Ca2+]i stimulation was produced
both by [Ca2+] mobilization from its intracellular stores and by
[Ca2+] entry into the cells. In conclusion, hGVEC express specific
type?2 BK receptors which enable specific BK-induced responses.
Received 31 October 1995; accepted in final form 30 April 1996.
APS Manuscript Number F371-5.
Article publication pending Am. J. Physiol. (Renal Fluid Electrolyte
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 5 June 96