Table 1

Effects of KB-R7943, which inhibits Na+/Ca2+ exchange, on the K+or veratridine-induced increase in cytosolic Ca2+ concentration in synaptosomes.

Method of DepolarizationKB-R7943
0 μM1 μM3 μM
K+ 100  ± 11%103  ± 7%88  ± 8%
(30 mM)1-a 1-b n.s.n.s.
Veratridine100  ± 5%94  ± 5%80  ± 6%
(10 μM)1-c n.s. 1-150 P< .05

These synaptosomes were preloaded with fura-2/AM (5 μM). For further details concerning the time schedule of stimulus application and drug addition, see Fig. 1. Given are the K+- or veratridine-induced increases in [Ca2+]i, expressed as the percentage of the controls (“0 μM KB-R7943”).

  • n.s., no significant difference.

  • ↵1-150 P < .05, compared with the corresponding controls.

  • ↵1-a Elevation of K+ concentration by 30 mM above the basal level of 4.8 mM.

  • ↵1-b Means ± S.E.M. of seven to eight experiments.

  • ↵1-c Means ± S.E.M. of eight experiments.