Table 2

The effect of physostigmine does not depend on the TM domain

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&α–14421 ± 108194121 ± 10591.38 ± 0.0351–, <0.001
βα&α(TM1 to TM3)–15034 ± 3105120.98316 ± 618<0.0011.28 ± 0.06110.19, 0.001
βα&α(TM3 to C)–27249 ± 333917<0.00182 ± 24100.371.19 ± 0.0470.03, 0.005
βα&β–1007 ± 116913.7 ± 0.5570.72 ± 0.0528–, <0.001
βα&β(TM1 to TM3)–959 ± 162280.972.3 ± 0.3250.140.76 ± 0.05140.82, 0.001
βα&β(TM3 to C)–1801 ± 54360.144.6 ± 1.160.740.63 ± 0.0630.80, 0.03
  • Chimeric subunits are named as subunit contributing the amino terminus followed by the region swapped between subunits (in parentheses), so α(M1–M3) indicates an α4 subunit containing β2 sequence for the TM1–TM3 domains. The joining points for the chimeras were as follows: start of TM1 α4 V(208)IRR β2 V(204)IRR, end of TM3 α4N(344)VHH β2 (N(340)VHH. 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.