Intracellular pH regulation in ventral horn neurones cultured from embryonic rat spinal cord.
Intracellular pH was measured with the pH-sensitive fluorescent probe BCECF in spinal cord neurones cultured from rat embryos. At an external pH of 7.3, the average steady-state pHi was 7.18 +/- 0.03 (SEM, n = 97) and 7.02 +/- 0.01 (n = 221) in HEPES-buffered and in bicarbonate-buffered medium, respectively. In both external media, pHi was strongly dependent on external pH (pHe). In HEPES-buffered medium, pHi recovery following an acid load induced by transient application of ammonium required external Na+ and was inhibited by amiloride, indicating the presence of a Na+/H+ exchange. Na(+)- and HCO3(-)-dependent, DIDS-sensitive alkalinizing mechanisms also contributed to pHi regulation in CO2/bicarbonate-buffered medium. The presence of an electrogenic Na(+)-HCO3- cotransporter was confirmed by the alkalinizing effect of KCl application. The fact that pHi is lower in CO2/bicarbonate- than in HEPES-buffered medium and the alkalinization observed upon suppression of external Cl- suggest that the acidifying Cl-/HCO3- transporter plays an important role in defining pHi.
Brechenmacher
C
C
Laboratoire de Neurobiologie Cellulaire, CNRS FRE 2180, Strasbourg, France.
Rodeau
J L
JL
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D000136:Acid-Base Equilibrium / Q000502:physiology*; D000584:Amiloride / Q000494:pharmacology; D000643:Ammonium Chloride / Q000494:pharmacology; D000818:Animals; D000870:Anterior Horn Cells / Q000196:embryology / Q000378:metabolism*; D017920:Antiporters / Q000378:metabolism*; D002021:Buffers; D002555:Cerebrospinal Fluid / Q000737:chemistry; D003470:Culture Media / Q000737:chemistry; D004622:Embryo, Mammalian / Q000378:metabolism; D005452:Fluoresceins / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D051381:Rats; D017693:Sodium Bicarbonate / Q000378:metabolism
D017920:Antiporters; D002021:Buffers; D003470:Culture Media; D005452:Fluoresceins; D005456:Fluorescent Dyes; D000643:Ammonium Chloride; D000584:Amiloride; C043829:2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein; D017693:Sodium Bicarbonate; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid