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Chloride dependence of intracellular pH in frog skin: a /sup 31/P NMR study

Conference · · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)
OSTI ID:5449894
Single frog skins from Northern Variety Rana pipiens were analyzed by /sup 31/P NMR spectroscopy during superfusion alternately with control and experimental Ringer's solutions, permitting each preparation to serve as its own control. The spectral positions of intracellular inorganic phosphate and extracellular methylphosphonate permitted continuous monitoring of intracellular (pH/sub c/) and extracellular (pH/sub 0/) pH, respectively. Acute and steady state measurements suggested that pH/sub c/ is well regulated at about 7.29 +- 0.05 over an external pH range of about 7.25-7.65. Below this range, pH/sub c/ decreased markedly when the external pH was reduced with nonvolatile acid. In the presence of 2.5 mM HCO/sub 3//sup -/ and 1% CO/sub 2/, total substitution of external Cl/sup -/ by gluconate reversibly increased pH/sub c/ by 0.34 +- 0.05 U (mean +- SE). Replacing external Cl/sup -/ by SO/sup 2 -//sub 4/ increased pH/sub c/ by 0.12 +- 0.01 in the presence of external HCO/sup -//sub 3/, but only by 0.05 +- 0.02 in its absence. SITS (1 mM) at a pH/sub 0/ of 6.95 +- 0.05 did not significantly alter pH/sub c/, but entirely prevented the steady state alkalinization characteristically induced by gluconate substitution for external Cl/sup -/. The results document that: (1) intracellular pH is maintained relatively constant when the external pH is varied over the physiologic range by adding fixed acid or base, and (2) this regulation is (at least in part) a reflection of Cl/HCO/sub 3/ antiport activity.
Research Organization:
Univ. of Pennsylvania School of Medicine, Philadelphia
OSTI ID:
5449894
Report Number(s):
CONF-8604222-
Conference Information:
Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:3
Country of Publication:
United States
Language:
English