On the role of bicarbonate as a hydrogen ion buffer in rat CNS neurones.
The role of bicarbonate as a hydrogen ion buffer has been investigated using the fluorescent dye BCECF in individual rat cerebellar, hippocampal and neocortical neurones maintained in culture. The steady-state intracellular pH (pHi) was estimated to be 7.07 +/- 0.05 (n = 22) in CO2-HCO3(-)-buffered media. Buffering power (beta) estimated from the addition and removal of weak bases was ca 10 mM (pH unit)-1 and was found to be similar in both CO2-HCO3(-)- and Hepes-buffered media. The membrane-permeant carbonic anhydrase inhibitor, acetazolamide (10-20 microM), did not affect estimates of beta. The results indicate that CO2-HCO3- does not act as an open buffer system in these neurones.
Amos
B J
BJ
Department of Physiology, Royal Free Hospital School of Medicine, London, UK.
Pocock
G
G
Richards
C D
CD
D000086:Acetazolamide / Q000494:pharmacology; D000643:Ammonium Chloride / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D001639:Bicarbonates / Q000494:pharmacology*; D002021:Buffers; D002257:Carbonic Anhydrase Inhibitors / Q000494:pharmacology; D002490:Central Nervous System / Q000166:cytology* / Q000378:metabolism / Q000502:physiology; D002531:Cerebellum / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005452:Fluoresceins; D005456:Fluorescent Dyes; D006863:Hydrogen-Ion Concentration; D008744:Methylamines / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D051381:Rats
D001639:Bicarbonates; D002021:Buffers; D002257:Carbonic Anhydrase Inhibitors; D005452:Fluoresceins; D005456:Fluorescent Dyes; D008744:Methylamines; D000643:Ammonium Chloride; C043829:2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein; D000086:Acetazolamide