Zm. Zhu et al., LOW CONCENTRATIONS OF OUABAIN INCREASE CYTOSOLIC-FREE CALCIUM-CONCENTRATION IN RAT VASCULAR SMOOTH-MUSCLE CELLS, Clinical science, 90(1), 1996, pp. 9-12
1. Low ouabain concentrations in the nanomolar range significantly inc
reased cytosolic free calcium concentration. 2. The ouabain-induced cy
tosolic free calcium concentration increase was due to transplasmamemb
rane calcium influx, which could be prevented in the absence of extrac
ellular calcium or by addition of the calcium channel blocker nifedipi
ne. 3. The amount of stored cellular Ca2+, as determined by the thapsi
gargin-induced cytosolic free calcium concentration increase, was also
enhanced by 1 nmol/l ouabain. 4. It is concluded that low ouabain con
centrations affect intracellular cytosolic free calcium concentration
homoeostasis.