ISSN:
1432-1424
Keywords:
chloride transport
;
equivalent circuit
;
cable analysis
;
fluid transport
;
ouffers
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Summary The effects of bathing solution HCO 3 − /CO2 concentrations on baseline cell membrane voltages and resistances were measured inNecturus gallbladder epithelium with conventional intracellular microelectrode techniques. Gallbladders were bathed in either low HCO 3 − /CO2 Ringer's solutions (2.4mm HCO 3 − /air or 1mm HEPES/air) or a high HCO 3 − /CO2 Ringer's (10mm HCO 3 − /1% CO2). The principal finding of these studies was that the apical membrane fractional resistance (fR a) was higher in tissues bathed in the 10mm HCO 3 − /CO2 Ringer's, averaging 0.87±0.06, whereasfR a averaged 0.63±0.07 and 0.48±0.08 in 2.4mm HCO 3 − and 1mm HEPES, respectively. Intraepithelial cable analysis was employed to obtain estimates of the individual apical (R a) and basolateral membrane (R b) resistances in tissues bathed in 10mm HCO 3 − /1% CO2 Ringer's. Compared to previous resistance measurements obtained in tissues bathed in a low HCO 3 − /CO2 Ringer's, the higher value offR a was found to be due to both an increase inR a and a decrease inR b. The higher values offR a and lower values ofR b confirm the recent observations of others. To ascertain the pathways responsible for these effects, cell membrane voltages were measured during serosal solution K+ and Cl− substitutions. The results of these studies suggest that an electrodiffusive Cl− transport mechanism exists at the basolateral membrane of tissues bathed in a 10mm HCO 3 − /1% CO2 Ringer's, which can explain in part the fall inR b. The above observations are discussed in terms of a stimulatory effect of solution [HCO 3 − /PCO2 on transepithelial fluid transport, which results in adaptive changes in the conductive properties of the apical and basolateral membranes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01870454
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