Effects of pH on the potassium current in rabbit corneal epithelial cells

Adam Rich, Christopher Bartling, Gianrico Farrugia, James L. Rae

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

The effects of pH on K+ conductance were measured using the amphotericin perforated-patch whole cell voltage-clamp technique in freshly dispersed rabbit corneal epithelial cells. Bath perfusion with pH 6.00 Ringer solution after standard Ringer solution (pH 7.35) increased outward K+- selective current (I(K)) from 120 ± 29 to 312 ± 64 pA during a step depolarization to +50 mV and hyperpolarized the resting membrane potential (E(m)) from -52 ± 5 to 62 ± 3 mV (n = 15, P ≤ 0.05). Increasing bath pH to 8.5 decreased I(K) from 183 ± 40 to 114 ± 35 pA (n = 6, P ≤ 0.05) and depolarized E(m) from -63 ± 6 to -53 ± 5 mV (n = 6, P ≤ 0.05). Intracellular acidification using the weak electrolyte (NH4)2SO4 also increased I(K) from 83 ± 15 to 183 ± 20 pA (n = 4, P = 0.01) and hyperpolarized E(m) from -51 ± 8 to -68 ± 6 mV (P = 0.002). Intracellular alkalinization reduced I(K) to 66 ± 10 pA and depolarized E(m) to -36 ± 8 mV (P = 0.009). Single channel studies in perforated outside-out vesicles showed that a decrease in bath pH from 7.35 to 6.00 was accompanied by an increase in the single channel open probability (NP(o)) from 0.43 to 0.64 at an E(m) of 15 mV. NP(o) was also increased in cell-attached patches. The unitary conductance, measured from -100 to + 100 mV, was not changed. These results indicate that pH modulates I(K) in rabbit corneal epithelial cells by changes in NP(o).

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Cell Physiology
Volume272
Issue number2 41-2
StatePublished - Feb 1997

Fingerprint

Potassium
Epithelial Cells
Rabbits
Acidification
Depolarization
Clamping devices
Amphotericin B
Baths
Electrolytes
Membranes
Electric potential
Patch-Clamp Techniques
Membrane Potentials
Ringer's solution
Perfusion
N-(2-aminophenyl)-4-((benzyl(2-hydroxyethyl)amino)methyl) benzamide

Keywords

  • cornea
  • electrophysiology
  • potassium channels

ASJC Scopus subject areas

  • Cell Biology
  • Clinical Biochemistry
  • Physiology
  • Physiology (medical)

Cite this

Effects of pH on the potassium current in rabbit corneal epithelial cells. / Rich, Adam; Bartling, Christopher; Farrugia, Gianrico; Rae, James L.

In: American Journal of Physiology - Cell Physiology, Vol. 272, No. 2 41-2, 02.1997.

Research output: Contribution to journalArticle

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abstract = "The effects of pH on K+ conductance were measured using the amphotericin perforated-patch whole cell voltage-clamp technique in freshly dispersed rabbit corneal epithelial cells. Bath perfusion with pH 6.00 Ringer solution after standard Ringer solution (pH 7.35) increased outward K+- selective current (I(K)) from 120 ± 29 to 312 ± 64 pA during a step depolarization to +50 mV and hyperpolarized the resting membrane potential (E(m)) from -52 ± 5 to 62 ± 3 mV (n = 15, P ≤ 0.05). Increasing bath pH to 8.5 decreased I(K) from 183 ± 40 to 114 ± 35 pA (n = 6, P ≤ 0.05) and depolarized E(m) from -63 ± 6 to -53 ± 5 mV (n = 6, P ≤ 0.05). Intracellular acidification using the weak electrolyte (NH4)2SO4 also increased I(K) from 83 ± 15 to 183 ± 20 pA (n = 4, P = 0.01) and hyperpolarized E(m) from -51 ± 8 to -68 ± 6 mV (P = 0.002). Intracellular alkalinization reduced I(K) to 66 ± 10 pA and depolarized E(m) to -36 ± 8 mV (P = 0.009). Single channel studies in perforated outside-out vesicles showed that a decrease in bath pH from 7.35 to 6.00 was accompanied by an increase in the single channel open probability (NP(o)) from 0.43 to 0.64 at an E(m) of 15 mV. NP(o) was also increased in cell-attached patches. The unitary conductance, measured from -100 to + 100 mV, was not changed. These results indicate that pH modulates I(K) in rabbit corneal epithelial cells by changes in NP(o).",
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N2 - The effects of pH on K+ conductance were measured using the amphotericin perforated-patch whole cell voltage-clamp technique in freshly dispersed rabbit corneal epithelial cells. Bath perfusion with pH 6.00 Ringer solution after standard Ringer solution (pH 7.35) increased outward K+- selective current (I(K)) from 120 ± 29 to 312 ± 64 pA during a step depolarization to +50 mV and hyperpolarized the resting membrane potential (E(m)) from -52 ± 5 to 62 ± 3 mV (n = 15, P ≤ 0.05). Increasing bath pH to 8.5 decreased I(K) from 183 ± 40 to 114 ± 35 pA (n = 6, P ≤ 0.05) and depolarized E(m) from -63 ± 6 to -53 ± 5 mV (n = 6, P ≤ 0.05). Intracellular acidification using the weak electrolyte (NH4)2SO4 also increased I(K) from 83 ± 15 to 183 ± 20 pA (n = 4, P = 0.01) and hyperpolarized E(m) from -51 ± 8 to -68 ± 6 mV (P = 0.002). Intracellular alkalinization reduced I(K) to 66 ± 10 pA and depolarized E(m) to -36 ± 8 mV (P = 0.009). Single channel studies in perforated outside-out vesicles showed that a decrease in bath pH from 7.35 to 6.00 was accompanied by an increase in the single channel open probability (NP(o)) from 0.43 to 0.64 at an E(m) of 15 mV. NP(o) was also increased in cell-attached patches. The unitary conductance, measured from -100 to + 100 mV, was not changed. These results indicate that pH modulates I(K) in rabbit corneal epithelial cells by changes in NP(o).

AB - The effects of pH on K+ conductance were measured using the amphotericin perforated-patch whole cell voltage-clamp technique in freshly dispersed rabbit corneal epithelial cells. Bath perfusion with pH 6.00 Ringer solution after standard Ringer solution (pH 7.35) increased outward K+- selective current (I(K)) from 120 ± 29 to 312 ± 64 pA during a step depolarization to +50 mV and hyperpolarized the resting membrane potential (E(m)) from -52 ± 5 to 62 ± 3 mV (n = 15, P ≤ 0.05). Increasing bath pH to 8.5 decreased I(K) from 183 ± 40 to 114 ± 35 pA (n = 6, P ≤ 0.05) and depolarized E(m) from -63 ± 6 to -53 ± 5 mV (n = 6, P ≤ 0.05). Intracellular acidification using the weak electrolyte (NH4)2SO4 also increased I(K) from 83 ± 15 to 183 ± 20 pA (n = 4, P = 0.01) and hyperpolarized E(m) from -51 ± 8 to -68 ± 6 mV (P = 0.002). Intracellular alkalinization reduced I(K) to 66 ± 10 pA and depolarized E(m) to -36 ± 8 mV (P = 0.009). Single channel studies in perforated outside-out vesicles showed that a decrease in bath pH from 7.35 to 6.00 was accompanied by an increase in the single channel open probability (NP(o)) from 0.43 to 0.64 at an E(m) of 15 mV. NP(o) was also increased in cell-attached patches. The unitary conductance, measured from -100 to + 100 mV, was not changed. These results indicate that pH modulates I(K) in rabbit corneal epithelial cells by changes in NP(o).

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