Table 3

The E loop is important in determining the effect of physostigmine

Subunits injectedResponse to 1 mM AChACh EC50Response to physostigmine
Mean ± S.E.No. of CellsP value aMean ± S.E.No. of CellsP value aMean ± S.E.No. of CellsP value b
nAμM
βα&β–1007 ± 116913.7 ± 0.5570.72 ± 0.0528–, <0.001
βα&β(ABC)–511 ± 12041.06.1 ± 1.141.00.52 ± 0.0440.3, 0.001
βα&β(A)–479 ± 6651.08.0 ± 3.250.70.71 ± 0.0731.0, 0.06
βα&β(B)–323 ± 121130.812.6 ± 2.53<0.0010.71 ± 0.0561.0, 0.001
βα&β(C)–317 ± 8861.09.3 ± 1.660.30.69 ± 0.0551.0, 0.004
βα&β(D)–207 ± 3641.03.6 ± 0.641.00.66 ± 0.0441.0, 0.003
βα&β(E)–8437 ± 166214<0.0013.0 ± 0.3121.00.90 ± 0.0440.4, 0.1
βα&β(F)–244 ± 7741.03.2 ± 0.641.00.69 ± 0.0131.0, 0.002
αβ&β–341 ± 98322.9 ± 0.5140.78 ± 0.0710–, 0.01
αβ&β(ABC)–68 ± 2740.65.7 ± 0.720.020.63 ± 0.0020.7, <0.001
αβ&β(E)–236 ± 5141.07.6 ± 1.440.81.00 ± 0.0740.2, 1.0
βα&α–14421 ± 108194121 ± 10591.38 ± 0.0351–, <0.001
βα&α(E)–24237 ± 2810240.0073.7 ± 0.414<0.0010.53 ± 0.0211<0.001, <0.001
αβ&α–7238 ± 11796878 ± 5471.51 ± 0.0825–, <0.001
αβ&α(E)–387 ± 10560.093.1 ± 0.25<0.0010.59 ± 0.034<0.001,0.001
βαβαα–2020 ± 26525153 ± 1291.43 ± 0.238–, 0.1
βαβαα(E)–1674 ± 50790.54.6 ± 0.67<0.0011.08 ± 0.1880.2, 0.7
βαβαβ–110 ± 23203.2 ± 0.8160.54 ± 0.046–, <0.001
βαβαβ(E)–265 ± 70160.97.8 ± 1.3110.0021.20 ± 0.18120.03, 0.3
βαβ(E)–αβ–2592 ± 67712<0.0014.6 ± 0.470.61.01 ± 0.1960.2, 1.0
  • Chimeric subunits are named as subunit contributing the amino terminus followed by the region swapped between subunits (in parentheses), so β(ABC) indicates a β2 subunit containing α4 sequence for the A, B and C loops. The locations of the chimeras are shown in Figure 2. Means ± S.E. and the number of cells are presented for the response to 1 mM ACh, for the concentration of ACh producing a half–maximal response EC50), and for the ratio of the response to a low concentration of ACh in the presence of physostigmine to the response of the same cell to ACh in the absence of physostigmine. Dashes indicate that that particular subunit combination was the comparison value for the P computation.

  • a P values give the significance of the difference in value to that of the first entry in the set (one–way analysis of variance with Dunnett correction).

  • b The first P value is the significance of the difference to the first entry in the set, whereas the second value is the difference of the potentiation to a value of 1 (i.e., no effect; one–sample t test). Dashes indicate that that particular subunit combination was the comparison value for the P computation.