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Stimulation of active sodium-potassium transport by hydrogen peroxide in cultured rabbit nonpigmented ciliary epithelium.
Curr Eye Res. 1999 Apr; 18(4):254-60.CE

Abstract

PURPOSE

Studies were conducted to examine the effect of hydrogen peroxide on active sodium-potassium transport in a cell line derived from nonpigmented ciliary epithelium of the rabbit eye.

METHODS

Studies were carried out using a rabbit nonpigmented ciliary epithelium cell line. 86Rb uptake by intact cells was measured in the presence or absence of ouabain. The ouabain-sensitive potassium (86Rb) uptake rate was used as an index of the rate of active sodium-potassium transport. Cell sodium content was measured by atomic absorption spectrophotometry. Na,K-ATPase activity was determined by measuring ATP hydrolysis in the presence or absence of ouabain, using membrane material isolated by centrifugation of cell homogenates.

RESULTS

Ouabain-sensitive potassium (86Rb) uptake rate measured in cells that had been preincubated with 200microM hydrogen peroxide for either 30 min or 60 min was increased to 196% and 181% of the control uptake rate, respectively. Lesser concentrations of hydrogen peroxide caused lesser degrees of stimulation. 200microM hydrogen peroxide caused an increase of cell sodium content. Such a change of cell sodium content is likely to be responsible, at least in part, for the observed stimulation of active sodium-potassium transport. However, the response may also be partly dependent on activation of a protein kinase since the serine/threonine protein kinase inhibitors staurosporine (1microM) and H-89 (20microM) were both found to prevent the stimulatory effect of 200microM hydrogen peroxide on ouabain-sensitive potassium (86Rb) uptake. Interestingly, neither H-89 nor staurosporine prevented the elevation of sodium content in cells that received 200microM hydrogen peroxide.

CONCLUSIONS

Taken together, these findings suggest a low concentration of hydrogen peroxide causes increased sodium entry into the cell and also activates a protein kinase-dependent mechanism for sodium pump stimulation. The protein kinase-dependent mechanism does not appear to be triggered by an increased rate of sodium entry since staurosporine did not prevent the stimulation of ouabain-sensitive potassium (86Rb) uptake elicited by an increase in sodium permeability caused by amphotericin B.

Authors+Show Affiliations

Department of Ophthalmology & Visual Science, University of Louisville School of Medicine, KY 40202, USA.No affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

10372984

Citation

Chin, S, and N A. Delamere. "Stimulation of Active Sodium-potassium Transport By Hydrogen Peroxide in Cultured Rabbit Nonpigmented Ciliary Epithelium." Current Eye Research, vol. 18, no. 4, 1999, pp. 254-60.
Chin S, Delamere NA. Stimulation of active sodium-potassium transport by hydrogen peroxide in cultured rabbit nonpigmented ciliary epithelium. Curr Eye Res. 1999;18(4):254-60.
Chin, S., & Delamere, N. A. (1999). Stimulation of active sodium-potassium transport by hydrogen peroxide in cultured rabbit nonpigmented ciliary epithelium. Current Eye Research, 18(4), 254-60.
Chin S, Delamere NA. Stimulation of Active Sodium-potassium Transport By Hydrogen Peroxide in Cultured Rabbit Nonpigmented Ciliary Epithelium. Curr Eye Res. 1999;18(4):254-60. PubMed PMID: 10372984.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Stimulation of active sodium-potassium transport by hydrogen peroxide in cultured rabbit nonpigmented ciliary epithelium. AU - Chin,S, AU - Delamere,N A, PY - 1999/6/18/pubmed PY - 1999/6/18/medline PY - 1999/6/18/entrez SP - 254 EP - 60 JF - Current eye research JO - Curr Eye Res VL - 18 IS - 4 N2 - PURPOSE: Studies were conducted to examine the effect of hydrogen peroxide on active sodium-potassium transport in a cell line derived from nonpigmented ciliary epithelium of the rabbit eye. METHODS: Studies were carried out using a rabbit nonpigmented ciliary epithelium cell line. 86Rb uptake by intact cells was measured in the presence or absence of ouabain. The ouabain-sensitive potassium (86Rb) uptake rate was used as an index of the rate of active sodium-potassium transport. Cell sodium content was measured by atomic absorption spectrophotometry. Na,K-ATPase activity was determined by measuring ATP hydrolysis in the presence or absence of ouabain, using membrane material isolated by centrifugation of cell homogenates. RESULTS: Ouabain-sensitive potassium (86Rb) uptake rate measured in cells that had been preincubated with 200microM hydrogen peroxide for either 30 min or 60 min was increased to 196% and 181% of the control uptake rate, respectively. Lesser concentrations of hydrogen peroxide caused lesser degrees of stimulation. 200microM hydrogen peroxide caused an increase of cell sodium content. Such a change of cell sodium content is likely to be responsible, at least in part, for the observed stimulation of active sodium-potassium transport. However, the response may also be partly dependent on activation of a protein kinase since the serine/threonine protein kinase inhibitors staurosporine (1microM) and H-89 (20microM) were both found to prevent the stimulatory effect of 200microM hydrogen peroxide on ouabain-sensitive potassium (86Rb) uptake. Interestingly, neither H-89 nor staurosporine prevented the elevation of sodium content in cells that received 200microM hydrogen peroxide. CONCLUSIONS: Taken together, these findings suggest a low concentration of hydrogen peroxide causes increased sodium entry into the cell and also activates a protein kinase-dependent mechanism for sodium pump stimulation. The protein kinase-dependent mechanism does not appear to be triggered by an increased rate of sodium entry since staurosporine did not prevent the stimulation of ouabain-sensitive potassium (86Rb) uptake elicited by an increase in sodium permeability caused by amphotericin B. SN - 0271-3683 UR - https://www.unboundmedicine.com/medline/citation/10372984/Stimulation_of_active_sodium_potassium_transport_by_hydrogen_peroxide_in_cultured_rabbit_nonpigmented_ciliary_epithelium_ L2 - https://www.tandfonline.com/doi/full/10.1076/ceyr.18.4.254.5359 DB - PRIME DP - Unbound Medicine ER -