The equilibrium CO2+H2O right arrow over left arrow H++HCO3- had made it impossible to determine how isolated changes in basolateral CO2 ([CO2]) or HCO3- concentration ([HCO3-]), at a fixed basolateral pH, modulate renal HCO3- or reabsorption. In the present study, we have begun to address this issue by measuring HCO3- reabsorption (JHCO3) and intracellular pH (pHi) in isolated perfused rabbit ...

Bonanno, Joseph A., Yi Guan, Sergey Jelamskii, and Xiao Jun Kang. Apical and basolateral CO2-HCO3 2 permeability in cultured bovine corneal endothelial cells. Am. J. Physiol. 277 (Cell Physiol. 46): C545–C553, 1999.—Corneal endothelial function is dependent on HCO3 2 transport. However, the relative HCO3 2 permeabilities of the apical and basolateral membranes are unknown. Using changes in intr...

Rates of cellular uptake of CO2 and HCO3 during steady-state photosynthesis were measured in the marine diatoms Thalassiosira weissflogii and Phaeodactylum tricornutum, acclimated to CO2 partial pressures of 36, 180, 360, and 1,800 ppmv. In addition, in vivo activity of extracellular (eCA) and intracellular (iCA) carbonic anhydrase was determined in relation to CO2 availability. Both species re...

Bonanno, Joseph A., Yi Guan, Sergey Jelamskii, and Xiao Jun Kang. Apical and basolateral CO2-HCO3 2 permeability in cultured bovine corneal endothelial cells. Am. J. Physiol. 277 (Cell Physiol. 46): C545–C553, 1999.—Corneal endothelial function is dependent on HCO3 2 transport. However, the relative HCO3 2 permeabilities of the apical and basolateral membranes are unknown. Using changes in intr...

At 5 degree C addition of CO2 or HCO3- to CO (HCO3-)-depleted thylakoids (containing 100 mM formate) initiates, within 10 s, the activation of the Hill reaction in light. In contrast to HCO3- addition, where there is a lag of 6-8 s, the activation by CO2 addition is almost instantaneous. With CO2, prior addition of carbonic anhydrase produces a lag of about 6 s that approaches the lag observed ...

We used the absorbance spectrum of the pH-sensitive dye dimethylcarboxyfluorescein to monitor intracellular pH (pHi) in the isolated perfused S3 segment of the rabbit proximal tubule, and examined the effect on pHi of switching from a HEPES to a CO2/HCO3- buffer in the lumen and/or the bath (i.e., basolateral solution). Solutions were titrated to pH 7.40 at 37 degrees C. With 10 mM acetate pres...

Mass-spectrometric disequilibrium analysis was applied to investigate CO2 uptake and HCO3 2 transport in cells and chloroplasts of the microalgae Dunaliella tertiolecta and Chlamydomonas reinhardtii, which were grown in air enriched with 5% (v/v) CO2 (high-Ci cells) or in ambient air (low-Ci cells). Highand low-Ci cells of both species had the capacity to transport CO2 and HCO3 , with maximum r...

In order to clarify the interaction between CO2 diffusion and HCO3- shift in the red blood cell (RBC), HCO3- shift was measured by using a stopped flow method combined with fluorometry. When HCO3- entered the RBC, the intracellular PCO2 increased, causing a secondary outflow of CO2. Conversely, when HCO3- ions flowed out of the RBC, the resulting decrease of PCO2 caused an inward CO2 diffusion....

The mechanism of basolateral membrane base transport was examined in the in vitro microperfused rabbit proximal convoluted tubule (PCT) in the absence and presence of ambient CO2/HCO3- by means of the microfluorometric measurement of cell pH. The buffer capacity of the cells measured using rapid NH3 washout was 42.8 +/- 5.6 mmol.liter-1.pH unit-1 in the absence and 84.6 +/- 7.3 mmol.liter-1.pH ...

Gu, Xiang Q., Hang Yao, and Gabriel G. Haddad. Effect of extracellular HCO3 2 on Na channel characteristics in hippocampal CA1 neurons. J Neurophysiol 84: 2477–2483, 2000. The effect of HCO3 /CO2 on membrane properties of isolated hippocampal CA1 neurons was studied with the use of the whole cell configuration of the patch-clamp technique. Neurons were acutely dissociated from 21to 30-day-old m...