1 ), ACSF with added tetrodotoxin (TTX) and in nominally Ca(2+)-free ACSF with added TTX.

2         In slices pre-incubated for 3-6 h in nominally Ca(2+)-free artificial cerebrospinal fluid, 5

3                 This change was abolished in nominally Ca(2+)-free conditions and markedly attenuated

4                                              Nominally Ca(2+)-free external solution abolished the SP

5 vels (< 10 nM) by inclusion of 1 mM BAPTA in nominally Ca(2+)-free external solution, Icat could stil

6  for inward current was 33.9 +/- 2.1 pS in a nominally Ca(2+)-free extracellular solution.

7 -mediated excitatory actions were found in a nominally Ca(2+)-free/high-Mg(2+) bath solution using ce

8 bation in 0 Ca(2+) medium (2 mM EGTA) but in nominally Ca(2+)-free medium (no added Ca(2+); 0 EGTA) a

9 ngle cell imaging showed a similar effect of nominally Ca(2+)-free medium and approximately 5% of cel

10 ntaining saline (5 min) and then returned to nominally Ca(2+)-free medium before stimulation, the [Ca

11 +)](i) transient, in >80% of cells bathed in nominally Ca(2+)-free medium.

12                            In comparison, in nominally Ca(2+)-free or EGTA-containing solution, the D

13                                       With a nominally Ca(2+)-free solution containing 10 microM cycl

14 wing store depletion by thapsigargin (TG) in nominally Ca(2+)-free solution was 94% greater and the [

15 naffected during superfusion of cells with a nominally Ca(2+)-free solution.

16 equimolar Co2+ or elevated (5-20 mM) Mg2+ in nominally Ca(2+)-free solutions was without effect.