AJP - Renal Physiology, Vol 251, Issue 5 831-F838, Copyright © 1986 by American Physiological Society
Intracellular pH regulation in frog skin: a 31P-nuclear magnetic resonance study
M. M. Civan and K. Peterson-Yantorno
The 31P-nuclear magnetic resonance spectra of single frog skins were
monitored during perfusion with reference and experimental solutions,
permitting each tissue to serve as its own series control. Over an external
pH (pHo) range of approximately 7.25-7.64 U, the intracellular pH (pHc)
displayed both homeostasis and response. External alkalinization produced a
transient intracellular regulation, but pHc returned to its base-line value
even in the absence of a further change in pHo. Below this range, pHc was
linearly and strongly dependent on pHo with a slope close to 1, when the
external pH was varied by addition of nonvolatile base. Measurements were
generally performed with tissues bathed in Ringer solutions containing 2.5
mM HCO3- and bubbled with 99% O2-1% CO2. Replacement of external Cl- by
gluconate reversibly increased pHc by 0.34 +/- 0.05 U. Substitution of
SO4(2-) for Cl- also alkalinized the cells; pHc was increased by 0.16 +/-
0.01 U in the presence of the standard concentration of external HCO3-, but
an alkaline shift was only just detectable (0.05 +/- 0.02 U) in its nominal
absence. The application of 1 mM
4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid blocked the
sustained intracellular alkalinization characteristically produced by
external Cl- replacement but did not alter the reduction in short-circuit
current and increase in transepithelial resistance caused by gluconate
substitution.(ABSTRACT TRUNCATED AT 250 WORDS)
