Table 2 Parameters relevant to calcium signalling.

From: Structural variability of dyads relates to calcium release in rat ventricular myocytes

 

CTR

IMY

P

Whole-cell patch-clamp measurements

JCa (pA/pF)

7.14 ± 0.66

7.09 ± 0.57

>0.5

TTP (ms)

5.23 ± 0.15

5.03 ± 0.27

>0.5

FDHM (ms)

7.77 ± 0.25

7.35 ± 0.18

0.18

V1/2 (mV)

–18.4 ± 0.6

–16.2 ± 0.9

0.08

Vr (mV)

55.7 ± 1.1

52.9 ± 1.4

0.14

Parameters of calcium spikes

CRS density

0.76 ± 0.02

0.73 ± 0.02

>0.5

Amp (ΔF/F0)

0.86 ± 0.02

1.00 ± 0.02

6.7E-7*

Lat (ms)

4.60 ± 0.21

5.56 ± 0.20

6.0E-9*

TTP (ms)

4.47 ± 0.10

5.48 ± 0.12

8.1E-10*

FDHM (ms)

8.43 ± 0.16

10.07 ± 0.16

1.3E-13*

Parameters of integral calcium release flux

Amp (ΔF/F0)

0.56 ± 0.02

0.63 ± 0.03

0.060

Lat (ms)

3.05 ± 0.11

3.64 ± 0.13

0.002

TTP (ms)

6.27 ± 0.14

7.82 ± 0.29

6.0E-5

FDHM (ms)

9.77 ± 0.24

11.97 ± 0.45

0.010*

  1. Data are given as mean ± s.e.m. estimated from 15 CTR and 17 IMY myocytes, except for V1/2 and Vr estimated from 5 CTR and 6 IMY myocytes. Parameters of calcium spikes were estimated from 218 CTR and 240 IMY spike records. The P values are for equal means between CTR and IMY groups estimated by Student’s t-test or Mann-Whitney test (*). JCa – calcium current density; TTP - time to peak amplitude; FDHM – full duration at half-maximum; V1/2 - half activation potential; Vr - reversal potential; CRS density – the number of calcium release sites per sarcomere; Amp - maximal amplitude, Lat - latency. JCa was determined as the peak ICa divided by membrane capacitance; V1/2 and Vr were determined from of ICa-V curves; ICa parameters Amp, TTP, and FDHM were determined from calcium currents at 0 mV. The parameters Amp, Lat, TTP, and FDHM of calcium spikes and of integral CRFs were determined from the respective best-fit curves.
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