P. Drescher et al., ROLE OF INTRACELLULAR CALCIUM STORES IN CONTRAST MEDIUM-INDUCED RENALVASOCONSTRICTION, Academic radiology, 3(11), 1996, pp. 912-918
Rationale and Objectives. Renovascular smooth muscle contractility, an
important factor in contrast media-induced nephrotoxicity, depends on
intracellular Ca2+ concentration, which is composed of extracellular
Ca2+ influx and intracellular Ca2+ release. These factors were investi
gated in contrast media-induced renal vasoconstriction in an in vitro
model. Methods. KCl-induced isometric contractions of rabbit renal art
ery were compared with contractions elicited by contrast media (diatri
zoate, iohexol, iopamidol). Measurements were made after incubation wi
th the Ca2+ channel blockers nifedipine, verapamil, and diltiazem to a
ssess the role of extracellular Ca2+ influx and after ryanodine and th
apsigargin to investigate the role of intracellular Ca2+ release. Resu
lts. The Ca2+ channel blockers partially inhibited contractions induce
d by contrast media, while KCl-induced contractions were completely ab
olished. Ryanodine and thapsigargin also markedly inhibited contrast m
edia-induced contractions. Conclusion. Ionic and nonionic contrast med
ia induced quantitatively different renal vasocontractions. Ca2+ chann
el blockers inhibited this vasocontraction only slightly compared with
intracellular Ca2+ release blockers.