. 2023 Mar 27;14:1127545. doi: 10.3389/fphys.2023.1127545

TABLE 1.

Characteristic parameters of the TG-induced Ca²⁺ mobilisation in HEK-293 cells. Experimental conditions, in which the parameters were obtained, are given on the left side. Cell and ER area, areas of the respective cross-sections in LSM images; ER area/cell area, ratio of ER to cell areas; TG, thapsigargin; IONO, ionomycin; b[Ca²⁺]_cyt, basal cytosolic Ca²⁺; b[Ca²⁺]_ER, basal ER Ca²⁺; pΔ[Ca²⁺]_cyt, peak amplitude of Ca²⁺ transients; AUC, area under the curve; k_leak, ER Ca²⁺ leak rate; τ_leak, time constant of ER Ca²⁺ leak; k_depl, ER Ca²⁺ depletion rate; τ_depl, time constant of ER Ca²⁺ depletion; k_clear, Ca²⁺ clearance rate; τ_clear, time constant of cytosolic Ca²⁺ clearance. Data on the right side is presented as mean ± SEM. Number of cells: 21–472.

Cell and ER dimensions
	Cell area	618.43 ± 26.34 µm²
	ER area	376.05 ± 14.84 µm²
	ER area/cell area	61.62 ± 0.82 %
Basal Ca²⁺ levels
zero [Ca²⁺]_ext	b[Ca²⁺]_cyt	62.90 ± 0.79 nM
	b[Ca²⁺]_ER	370.59 ± 35.60 µM
1 mM [Ca²⁺]_ext	b[Ca²⁺]_cyt	67.76 ± 0.94 nM
10 mM [Ca²⁺]_ext	b[Ca²⁺]_cyt	97.04 ± 2.67 nM
Cytosolic Ca²⁺ transients
zero [Ca²⁺]_ext/1 μM TG	pΔ[Ca²⁺]_cyt	0.56 ± 0.01 µM
	AUC	133.31 ± 1.14 μM⋅s
1 mM [Ca²⁺]_ext/1 μM TG	pΔ[Ca²⁺]_cyt	1.06 ± 0.01 µM
	AUC	474.21 ± 4.32 μM⋅s
10 mM [Ca²⁺]_ext/1 μM TG	pΔ[Ca²⁺]_cyt	1.61 ± 0.05 µM
	AUC	675.73 ± 14.41 μM⋅s
Total cellular Ca²⁺ content
zero [Ca²⁺]_ext/10 µM IONO	pΔ[Ca²⁺]_cyt	2.11 ± 0.04 µM
	AUC	108.15 ± 1.59 μM⋅s
ER and non-ER Ca²⁺ content
zero [Ca²⁺]_ext/1 μM TG	pΔ[Ca²⁺]_cyt	0.52 ± 0.01 µM
	AUC	116.02 ± 1.43 μM⋅s
zero [Ca²⁺]_ext/10 µM IONO	pΔ[Ca²⁺]_cyt	0.23 ± 0.01 µM
	AUC	50.25 ± 0.51 μM⋅s
ER Ca²⁺ depletion
zero [Ca²⁺]_ext/1 μM TG	k_depl	6.12 e−3 ± 0.97 e−3 s⁻¹
	τ_depl	162.41 ± 7.81 s
ER Ca²⁺ efflux (Ca²⁺ leak)
zero [Ca²⁺]_ext/1 μM TG	k_leak	15.41 e−3 ± 2.53 e−3 s⁻¹
	τ_leak	77.48 ± 8.06 s
External Ca²⁺ influx (SOCE)
1 mM [Ca²⁺]_ext/1 μM TG	pΔ[Ca²⁺]_cyt	1.85 ± 0.04 µM
10 mM [Ca²⁺]_ext/1 μM TG	pΔ[Ca²⁺]_cyt	3.41 ± 0.05 µM
Cytosolic Ca²⁺ clearance
zero [Ca²⁺]_ext/2 mM EGTA	k_clear	28.34 e−3 ± 1.02 e−3 s⁻¹
	τ_clear	37.08 ± 1.43 s