Table 1.

Passive and active membrane properties of wild-type and STIM1PKO mice

SpikeWild-type miceSTIM1PKO micep Value
Cm (pF)644.9 ± 12.7634.5 ± 14.00.586
Rin (MΩ)43.9 ± 1.138.1 ± 1.0<0.001***
First spike latency (ms)16.5 ± 0.518.0 ± 0.90.137
Rheobase (pA)261.1 ± 9.1281.6 ± 11.20.159
Threshold (mV)1st spike−47.0 ± 0.3−46.0 ± 0.50.080
25th spike−43.1 ± 0.4−41.9 ± 0.50.070
AP amplitude (mV)1st spike82.0 ± 1.082.4 ± 1.10.775
25th spike70.6 ± 1.071.4 ± 1.00.545
FWHM (ms)1st spike0.205 ± 0.0040.195 ± 0.0030.031*
25th spike0.226 ± 0.0050.211 ± 0.0030.012*
Upstroke (V/s)1st spike542.6 ± 10.1570.1 ± 10.30.059
25th spike421.0 ± 9.8448.5 ± 8.80.039*
Downstroke (V/s)1st spike−452.9 ± 10.9−466.0 ± 9.60.368
25th spike−368.8 ± 10.3−385.9 ± 9.10.214
Slope of postspike depolarization (V/s)1st spike1.69 ± 0.031.62 ± 0.050.234
25th spike1.19 ± 0.031.01 ± 0.04<0.001***
ISI (ms)1st spike10.4 ± 0.210.7 ± 0.30.402
25th spike14.4 ± 0.317.3 ± 0.8<0.001***
fAHP (mV)1st spike14.6 ± 0.314.3 ± 0.40.581
25th spike15.8 ± 0.315.9 ± 0.40.830
mAHP (mV)8.5 ± 0.310.9 ± 0.3<0.001***

  • Several parameters, including Rin, slope of postspike depolarization, ISI, and mAHP were significantly different in STIM1PKO mice compared to wild-type littermates (p < 0.001). Active properties of the 25th spike showed more differences than those of the 1st spike. Slope of postspike depolarization, especially, were remarkably lowered in STIM1PKO mice, which could explain the increase of ISI despite the shortened action potential waveform (p < 0.05). Up-stroke and down-stroke, rising and falling phase of action potential, respectively. Data were from the experiment performed in Figure 5. Data are expressed as the mean ± SEM.

  • ↵*p < 0.05, independent-samples t test.

  • ↵***p < 0.001, independent-samples t test.