Table 3.

The effects of inhibiting Na⁺-Ca²⁺ exchanger activity either by clamping at +130 mV or replacement of [Na⁺]_o with LiCl on rates of decline in [Ca²⁺]_c at room temperature

	InsP3			Caffeine			Depolarisation
	d[Ca2+]c/dt (nM s−1)	[Ca2+]c (nM)	n	d[Ca2+]c/dt (nM s−1)	[Ca2+]c (nM)	n	d[Ca2+]c/dt (nM s−1)	[Ca2+]c (nM)	n
Control	70 ± 19	200	4	—	—	—	50 ± 14	300	3
+130 mV	59 ± 14	200	4	—	—	—	53 ± 12	300	3
Control	123 ± 15	300	10	31 ± 11	200	4	48 ± 10	200	6
Na+ replaced by LiCl	126 ± 16	300	10	35 ± 7	200	4	37 ± 12	200	6

Rates of decline (d[Ca²⁺]_c/dt± s.e.m.) were measured at a given Ca²⁺ concentration (nM) of Ca²⁺ transients evoked by InsP₃, caffeine and depolarisation. n, number of experiments. Depolarisation was usually from −70 mV to 0 mV.