Table 2.

Activation and desensitization of WT and mutant 5-HT₃ receptors

M2 4′ amino acid	Activation (10–90% rise time, ms)	Desensitization (t1/2, s)
K (WT)	103 ± 9 (11)	5.0 ± 0.5 (12)
R	106 ± 15 (7)	26.6 ± 2.8 (11)*
Q	115 ± 16 (6)	8.2 ± 0.8 (11)*
S	99 ± 10 (6)	11.2 ± 1.2 (10)*
G	119 ± 6 (5)	20.3 ± 2.0 (11)*

Data are means ± s.e.m. of (n) independent experiments.

^*Significantly different from WT (Student's t test, P < 0.05).