Table 1 IC50 values for PhTX-343 inhibition of nAChR subunit combinations.

From: Block of nicotinic acetylcholine receptors by philanthotoxins is strongly dependent on their subunit composition

 

VH (mV)

n

PhTX-343 IC50 (95% CI), μM

Peak

Late

α4β2

−60

7

1.90

(1.01–3.60)

0.46

(0.28–0.75)

−80

7

0.93

(0.41–2.09)

0.31

(0.18–0.54)

−100

7

0.14

(0.09–0.22)

0.08

(0.049–0.132)

α4β2(V253F)

−60

14

0.62

(0.30–1.28)

0.063

(0.045–0.089)

−80

10

0.75

(0.46–1.23)

0.12

(0.06–0.23)

−100

8

0.11

(0.07–0.17)

0.014

(0.011–0.016)

α4β4

−60

9

0.97

(0.60–1.58)

0.17

(0.12–0.24)

−80

9

0.35

(0.24–0.50)

0.065

(0.047–0.089)

−100

6

0.29

(0.18–0.46)

0.027

(0.020–0.036)

α3β4

−60

7

0.29

(0.21–0.40)

0.088

(0.065–0.120)

−80

8

0.080

(0.062–0.104)

0.012

(0.010–0.014)

−100

9

0.077

(0.059–0.102)

0.0077

(0.0063–0.0093)

α3β4(F255V)

−60

7

0.31

(0.23–0.42)

0.074

(0.060–0.091)

−80

9

0.038

(0.029–0.048)

0.012

(0.010–0.014)

−100

8

0.017

(0.011–0.024)

0.005

(0.0036–0.0068)

α3β2

−60

7

64.5

(7.8–532)

1.59

(1.20–2.11)

−80

12

9.26

(5.90–14.6)

1.37

(1.12–1.69)

−100

8

3.59

(1.58–8.19)

0.37

(0.29–0.48)

α7

−60

6

6.71

(5.39–8.35)

6.56†

(5.30–8.12)

−80

7

6.48

(5.12–8.21)

5.06†

(3.95–6.48)

−100

9

8.80

(6.92–11.18)

6.77†

(5.44–8.42)

α1β1γδ

−60

8

27.1

(19.1–38.4)

18.0

(12.8–25.4)

−80

8

15.1

(9.5–24.0)

11.9

(9.2–15.4)

−100

9

3.26

(2.54–4.17)

2.44

(1.50–3.97)

  1. IC50 values for PhTX-343 inhibition of both peak and late current estimated from concentration-inhibition curves in Figs 2 and 4.
    Figure 4
    figure 4

    The effect of M2 mutations β2(V253F) and β4(F255V) on PhTX-343 and PhTX-12 inhibition.

    Concentration-inhibition curves for PhTX-343 (A,B) and PhTX-12 (C,D) inhibition of α3β4 (blue ■), α3β4(F255V) (blue □), α4β2 (red ●) and α4β2(V253F) (red ○) peak (A,C) and late (B,D) current. The ACh concentrations were 10 μM for α4β2 and α4β2(V253F), and 100 μM for α3β4 and α3β4(F255V). VH = −80 mV. Curves are fitted by Eq. 1 and IC50 values are given in Tables 1 and 2.

    Full size image
  2. †For α7 this is based on the area under the current trace as there was no stable late current.
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