Table I.

Characterization of subcellular Ca^{2 +} signals in 3T3 fibroblasts

	Amplitudes	Area	Frequency	n
	nM	μm2	s−1
Basal
CD38−	44.3 ± 17.7	0.33 ± 0.08	ND	60
CD38− preinc. cADPR	64.3 ± 22.9	0.42 ± 0.16	ND	98
CD38− microinj. Ry	45.6 ± 18.2	0.36 ± 0.09	ND	60
CD38+	52.1 ± 14.9	0.34 ± 0.08	ND	91
ATP
CD38−	50.1 ± 15.3	0.34 ± 0.07	0.40 ± 0.39	78
CD38− preinc. cADPR	98.4 ± 29.6a	0.38 ± 0.14	1.13 ± 0.51a	111
CD38− microinj. Ry	87.2 ± 26.2a	0.36 ± 0.10	1.71 ± 0.66a	106
CD38+	96.0 ± 36.7a	0.35 ± 0.09	1.23 ± 0.42a	131

Confocal Ca²⁺ imaging in single Fura2-loaded 3T3 cells was carried out as described in the Materials and methods. During the basal period, images were acquired at low temporal resolution; thus, the frequency of signals was not determined (ND). Subcellular Ca²⁺ signals were analyzed in the first seconds upon ATP stimulation in 13–18 ROIs from three cells for each condition (n, number of individual signals analyzed in total for each condition). For the subcellular distribution of the subcellular signals, refer to Fig. 5. Data are presented as mean ± SD.

^aStatistically significant differences versus CD38⁻ cells (P ≤ 0.05, t test).