| Species | Original | Mutated to | Mutation |
| Human | Glu 176 |
|
|
| Rat Equivalent | Glu 180 | Gln | E180Q |
| Mouse Equivalent | Val 290 |
When this mutation was co-expressed with the WT b 2, the effect of 2mM Ca 2+ was eliminated. When it was the co-expressed with V262M , the Ca 2+ blocked the 30 m M ACh response. The I Ca 2+ /I 0 of the E180Q 30 m M ACh response was 0.85 +/- 0.05, but for E180Q/V262M, it was 0.60 +/- 0.01.
Also studied: a 4 S252F , a 4 +L264 , b 2 V262L and b 2 V262M .