Table 1.

Decay kinetics of Ca²⁺ signals incsp^U1 mutants and controls

	Control (6)	cspU1 (6)	p Value
5 Hz	2.78  ± 0.35	2.60  ± 0.62	0.803
15 Hz	2.99  ± 0.52	6.80  ± 0.51	<0.001
20 Hz	1.51  ± 0.08	5.19  ± 0.94	0.002
25 Hz	2.04  ± 0.81	3.40  ± 0.62	0.053
40 Hz	3.80  ± 0.75	10.08  ± 0.83	<0.001

Time constants (in seconds) were measured at five different frequencies in both csp^U1 and control preparations at 34°C. Values represent the mean ± SD. At all frequencies above 5 Hz, Ca²⁺ signals ofcsp^U1 preparations have a significantly longer time constant of decay than those of controls (p < 0.05, Student's t test).