Table 1.

Estimate of J_NBCe/J^tot_NBC in resting myocytes under normal conditions

	INBC (pA pF−1)	volume (pl)	JNBCe (mm min−1)	JtotNBC (mm min−1)	JNBCe/JtotNBC
Rat	0.04	18a	0.40	0.68	0.6
	(pHi 7.05)	32b	0.22	0.68	0.3
		44c	0.16	0.68	0.2
Rabbit	0.04	29d	0.28	0.42	0.7
	(pHi 7.00)	31e	0.26	0.42	0.6
		38f	0.22	0.42	0.5
Guinea pig	0.02	18a	0.18	0.32	0.6
	(pHi 7.07)	46c	0.08	0.32	0.3
		28g	0.12	0.32	0.4

It was assumed that electrogenic NBC had a 1 : 2 stoichiometry and J_NBCe (mm min⁻¹ l⁻¹) was given as: J_NBCe= 2(I_NBC× C_m)/(F× cell volume), where C_m is membrane capacitance (pF) and F is the Faraday constant. Values for C_m were 149 pF (rat), 175 pF (rabbit) and 155 pF (guinea pig). Values of I_NBC at −85 mV were taken from Fig. 7C and those for J^tot_NBC at the same pH_i were taken from Fig. 2A. Surface/volume ratios (μm²μm⁻³) were:

^a0.84 (Satoh et al. 1996),

^b0.46 (Page, 1978),

^c0.34 (Page et al. 1971),

^d0.60 (Page & Surdyk-Droske, 1979),

^e0.56 (Page, 1978),

^f0.46 (Satoh et al. 1996).

^gFixed volume of 28 pl (Campbell et al. 1987).