Table 5.

Comparison of transport properties for vascular endothelia

				Brain microvascular
Preparation	Aortic Umbilical vein endothelial cells	Pulmonary endothelial cells	endothelial cells endothelial cells	Other studies	This study
Basal pH with HCO3−	7.26	∼7.2		6.9, 7.18**	7.15
Basal pH without HCO3−	7.21	∼7.2, 7.08*	7.02	6.83	7.1
Intrinsic buffer capacity near 7.1	15 mm		69 mm		25 mm
Near pH 7.1	∼17 μm s−1	Yes		Yes*, yes**	∼4 μm s−1
Na+/H+ exchange
Na+-dependent HCO3− influx	yes	Yes			∼25 μm s−1
Cl− dependent	∼17 μm s−1				suggestion
Cl− independent					∼17 μm s−1
Na+-independent Cl−/HCO3− exchange		Yes	See note*†		∼28 μm s−1 when reversed by Cl− removal
after NH4Cl prepulse#.	Yes*	Yes*	Yes	Yes, yes**	∼270 μm s−1 at pH 6.36
Na+/H+ exchange	> 50 μm s−1 at pH 6.9
Na+-dependent HCO3− influx	Yes	Yes*		Yes
Cl− dependent	> 34 μm s−1 at pH 6.9	Yes*		Yes data not shown
Net transport	None	None	None	secretion: apical (blood) to basolateral (brain)
References	Sun et al. (1999)	Ziegelstein et al. (1992)	Cutaia & Parks (1996)	Sipos et al. (2005)	This study
	Escobales et al. (1990)*	Ziegelstein et al. (1998)	Cutaia et al. (1998)	Vigne et al. (1991)*
		Wittstein et al. 2000,Faber, 1998*	Nozik-Grayck et al. (2003)*	Hsu et al. (1996)**

All HCO₃⁻ transport indicated has been shown to be either DIDS or H₂DIDS sensitive, all Na⁺/H⁺ exchange has been shown to be sensitive to either EIPA or DMA, (#) or other form of imposed acidification.

^†Nozik-Grayck et al. (2003) demonstrated ·O_2•⁻/HCO₃⁻ exchange which was presumed to be mediated by the Na⁺-independent Cl⁻/HCO₃⁻ exchanger, AE2.