| Species | Original | Mutated to | Mutation |
| Human | Phe 102 |
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| Rat Equivalent | Phe 101 | ||
| Mouse Equivalent | Phe 107 |
5-HT3 F107Y has a lower affinity for 5-HT (Ki = 203 vs 16 nM) and a higher EC(50) value (11 vs 1.2 uM) compared to wild-type receptors.
Activation of maximal 5-HT-activated currents mediated by the mutant receptor was slower than those of the wild-type receptor.
The 5-HT3 F107N mutant has a higher affinity for 5-HT (1.6 vs 16 nM), a reduced EC50 for the agonist (0.2 vs 1.2 uM) compared to wid-type receptors.
The mutant F107N was activated by acetylcholine (EC50 = 260 uM). The response to acetylcholine was blocked by the 5-HT3 antagonist renzapride.