Channel

Activation
 
n



V_{0.5act}(mV)

k_{act.}

G_{max} (μS)

Peak at +10 mV (μA)
 

Ca_{V}2.1/β_{4}

2.60 ± 0.65

5.39 ± 0.49

8.45 ± 2.20

0.25 ± 0.05

16

Ca_{V}2.1/β_{4}/γ_{2}

4.27 ± 1.24

4.91 ± 0.52

9.96 ± 3.34

0.32 ± 0.12

14

Ca_{V}2.1/β_{4}/γ_{4}

5.70 ± 2.26

5.43 ± 0.47

8.16 ± 2.59

0.26 ± 0.07

11

Ca_{V}2.1/β_{4}/α2δ_{2}

4.60 ± 0.59

4.03 ± 0.15

14.97 ± 2.05 *

0.54 ± 0.08

43

Ca_{V}2.1/β_{4}/α2δ_{2}/γ_{2}

4.13 ± 0.63

4.46 ± 0.14

15.43 ± 1.96

0.54 ± 0.07

34

Ca_{V}2.1/β_{4}/α2δ_{2}/γ_{4}

5.56 ± 0.60

3.96 ± 0.24

14.8 ± 2.64

0.56 ± 0.10

20

 To analyze the voltagedependent activation, currentvoltage (IV) relationships (Figure 7A and Figure 7B) were fitted with a modified Boltzmann equation (see methods) to calculate V_{50act}, the midpoint of voltage dependence of activation, k_{act}, the slopefactor and G_{max}, the maximum conductance. Values are expressed as mean ± S. E. M. of the number of replicates, n. Oneway analysis of variance (ANOVA) tests determined no statistically significant changes in any pairs of data differing by the presence of a γ_{2} or γ_{4} P < 0.05 was considered significant). Statistically significant differences observed between the Ca_{V}2.1/β_{4} and Ca_{V}2.1/β_{4}/α2δ_{2} channels are indicated by * (P < 0.05).