Intracellular potential and pH of rabbit corneal endothelial cells

Ka, Bowman; Rd, Elijah; Ke, Cheeks; Green, K

doi:10.3109/02713688409011745

Cited by 14 publications

(5 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Previous attempts to demonstrate a contribution of the Na+-K+-pump to the resting potential of rabbit corneal endothelium (Bowman, Elijah, Cheeks & Green, 1984) or guinea-pig aortic endothelium (Northover, 1980) have been negative, probably due to limitations of the methods used. However, differences in the density of pump sites in vascular endothelium from various regions cannot be excluded (see Brock et al 1986;Freissmuth et al 1987).…”

Section: The Etectrogenic Sodium Pump In Confluent Monolayersmentioning

confidence: 99%

Passive electrical properties and electrogenic sodium transport of cultured guinea‐pig coronary endothelial cells.

Daut¹,

Mehrke²,

Nees³

et al. 1988

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. Coronary endothelial cells were isolated from adult guinea-pig hearts (Nees, Gerbes & Gerlach, 1981) and the electrical properties of primary cultures were studied using the tight-seal whole-cell recording mode of the patch clamp technique.2. On the third or fourth day in culture whole-cell clamp records from single coronary endothelial cells were obtained at 37 'C. The resting potential was -33 + 6 mV (n = 10). The membrane time constant determined with rectangular current pulses was 68 + 22 ms (n = 10).3. In voltage clamp experiments, no time-dependent membrane conductance changes were found in the range -80 to + 40 mV. The current-voltage relation was linear in normal physiological salt solution containing 5-4 mM-K+. The input resistance was 1P7 +0 4 GQ. When the external K+ concentration was increased to 116 mm the cells depolarized to about -3 mV and the clamp currents showed marked inward rectification.4. Between days four and seven in culture the endothelial cells formed confluent monolayers which showed the characteristic 'cobblestone' morphology. The input resistance of cells in a monolayer was 8 + 3 MQ, i.e. a factor of 200 lower than that found in single cells. It was concluded that the cells in the confluent monolayer are coupled electrically by gap junctions.5. Exposure of coronary endothelial cells to K+-free solution for 5 min produced a depolarization of about 8 mV. Upon readmission of normal external K+ the cells transiently hyperpolarized by up to 20 mV. This transient hyperpolarization decayed with a time constant of 1-9 + 0-3 min.6. The transient hyperpolarization could be abolished by application of 2 x 10-4 Mdihydro-ouabain (DHO). Application of DHO in the steady state produced a depolarization of 8+1 mV. From these findings it was concluded that coronary endothelial cells possess an electrogenic sodium pump which contributes about -8 mV to the resting potential.7. From the passive electrical properties of single cells and the morphological data t Present address:

show abstract

Section: The Etectrogenic Sodium Pump In Confluent Monolayersmentioning

confidence: 99%

Passive electrical properties and electrogenic sodium transport of cultured guinea‐pig coronary endothelial cells.

Daut¹,

Mehrke²,

Nees³

et al. 1988

The Journal of Physiology

View full text Add to dashboard Cite

show abstract

“…On a healthy ocular surface, the pH level of tear films ranges from 7.2 to 7.6 28 and remains relatively stable throughout the day owing to its inherent buffering capacity, [28][29][30][31] tear turnover rate, and tear drainage. 28,31 Although some in vitro studies have demonstrated that decreases in extracellular pH directly can reduce intracellular pH 32,33 and cause alternations in cell morphology and corneal cellular functions, 32,[34][35][36] Carney et al 37 showed that tear pH ranging from 7.0 to 7.7 showed increased resistance to pH changes when challenged with nonbuffered water pH ranging from 3.5 to 8.0. These authors suggested that the tear buffering capacity was more effective and substantial in response to pH changes when it was more acidic than basic.…”

Section: Discussionmentioning

confidence: 99%

Corneal Health during Three Months of Scleral Lens Wear

et al. 2020

View full text Add to dashboard Cite

SIGNIFICANCE This study evaluated the effects scleral lens wear has on corneal health using fluorometry and in vivo confocal microscopy. No subclinical changes on healthy corneas of young subjects were observed during 3 months of scleral lens wear. PURPOSE This study aimed to evaluate the effects 3 months of scleral lens wear has on the corneal epithelial barrier function, dendritic cell density, and nerve fiber morphology. METHODS Twenty-seven neophytes (mean [standard deviation] age, 21.4 [3.9] years) wore scleral lenses of a fluorosilicone acrylate material bilaterally (97 Dk, 15.6 to 16.0-mm diameter) for 3 months without overnight wear. Subjects were randomized to use either Addipak (n = 12) or PuriLens Plus (n = 15) during lens insertion. Measurements of corneal epithelial permeability to fluorescein were performed with automated scanning fluorophotometer (Fluorotron Master; Ocumetrics, Mountain View, CA) on the central cornea of the right eye and the temporal corneal periphery of the left eye. Images of the distributions of corneal nerve fibers and dendritic cells and nerve fibers were captured in vivo with a confocal laser scanning microscope (Heidelberg Retina Tomograph, Rostock Cornea Module; Heidelberg Engineering, Heidelberg, Germany) on the central and inferior peripheral cornea of the left eye. Corneal measurements and imaging were performed at baseline and after 1 and 3 months of lens wear. RESULTS The corneal permeability values in natural log, dendritic cell densities, and nerve fiber morphology did not significantly change from baseline to 1 and 3 months of lens wear, for both central and peripheral corneal regions (P > .05). Dendritic cell density at the inferior cornea was higher than the central cornea throughout the study (P < .001). No relationships were observed between each outcome measurements and the saline solution groups (P > .05). CONCLUSIONS Scleral lens wear for 3 months on healthy cornea of young subjects did not affect corneal epithelial barrier function, nerve fiber, and dendritic cell densities. Buffered and nonbuffered saline solutions impacted the corneal health in similar ways.

show abstract

“…Studies of the corneal epithelium have shown that pH regulates epithelial chloride secretion (Candia 1973;Fisher & Widerholt 1978;Rick et al 1985). In the corneal endothelium, pH regulates fluid transport (Fischbarg & Lim 1974), bicarbonate transport (Green et al 1981), barrier function aentsch 'et al 1985), intracellular potential (Bowman et al 1984), and corneal deturgescence (Walkenbach & Corwin 1987). These studies have examined the effect of tear film, aqueous humor, or medium pH on epithelial or endothelial function, or both.…”

Section: Discussionmentioning

confidence: 99%

“…They did not, however, measure intracorneal pH concurrently with storage-medium pH and relate changes in intracellular pH to corneal function. A few studies have directly determined endothelial (intracellular) pH and examined its relationship to corneal metabolic function (Green et al 1981;Hull et al 1983;Bowman et al 1984). In these studies intracellular pH was determined using the dimethyloxazolidine-dione method (Miller et al 1963).…”

Section: Discussionmentioning

confidence: 99%

pH of organ‐culture‐stored corneas

Lass

Greiner

Meneses³

et al. 1988

Acta Ophthalmologica

View full text Add to dashboard Cite

Changes in intracorneal and storage-medium pH values of organ-culture-stored cat corneas were monitored over a 4-week period. The intracorneal pH was determined using the phosphorus-31 magnetic resonance spectroscopy (31P MRS) chemical shift of inorganic orthophosphate in conjunction with a standard pH titration curve. We incubated 32 adult cat corneas using two similar standard organ-culture methods, one with chondroitin sulfate (method 1) and the other without (method 2). Time-course data at 0, 1, 3 and 4 weeks of storage were used to calculate the rate of pH change. The intracorneal pH was not changed significantly for either organ-culture method; however, the storage-medium pH rate of change declined significantly for both methods (method 1, 0.15 pH units/week; method 2, 0.12 pH units/week). The difference between intracorneal and storage-medium pH values over time increased at a rate of 0.12 and 0.11 pH units/week for method 1 and method 2, respectively. The declining storage-medium pH in conjunction with the maintenance of intracorneal pH contributes to an increased metabolic demand on the cornea.

show abstract

Intracellular potential and pH of rabbit corneal endothelial cells

Cited by 14 publications

References 21 publications

Passive electrical properties and electrogenic sodium transport of cultured guinea‐pig coronary endothelial cells.

Passive electrical properties and electrogenic sodium transport of cultured guinea‐pig coronary endothelial cells.

Corneal Health during Three Months of Scleral Lens Wear

pH of organ‐culture‐stored corneas

Contact Info

Product

Resources

About