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The Inhibition of Na, K-ATPase, and Mg-ATPase by Timolol Maleate in Cultured Non-Pigmented Epithelial Cells of the Ciliary Body
- Source :
- Journal of Ocular Pharmacology and Therapeutics. 8:107-114
- Publication Year :
- 1992
- Publisher :
- Mary Ann Liebert Inc, 1992.
-
Abstract
- Bovine, non-pigmented, ciliary body epithelial cells were isolated and grown in culture to determine whether timolol maleate might affect the activity of their plasma membrane ATPases. The possible effects were tested in drug concentrations in a range of 5 x 10(-19) to 5 x 10(-5) M over an incubation period of 30 min at 37 degrees. Assays of specific activity showed that the drug significantly (p less than .001 for most concentrations) inhibited both Na,K-ATPase and Mg-ATPase. However, the inhibition was partially reversed in concentrations greater than 10(-6) M for Na,K-ATPase and 10(-5) M for Mg-ATPase. The latter enzyme also indicated a second partial reversal in activity at concentrations between 10(-12) and 10(-9) M. These reversals in activity suggest that more than one binding site is involved in the inhibition of both enzymes. Since Na,K-ATPase in non-pigmented, ciliary body cells is responsible for the generation of aqueous fluid and the intraocular pressure (IOP), this inhibition demonstrates a possible mechanism for the pharmacological action of timolol maleate in lowering IOP.
- Subjects :
- medicine.medical_specialty
ATPase
Molecular Sequence Data
Timolol
Ciliary body
Internal medicine
medicine
Animals
Pharmacology (medical)
Amino Acid Sequence
Na+/K+-ATPase
Ouabain
Pigment Epithelium of Eye
Cells, Cultured
Pharmacology
Binding Sites
biology
Chemistry
Cell Membrane
Ciliary Body
Biological activity
Molecular biology
Ophthalmology
medicine.anatomical_structure
Endocrinology
Mechanism of action
Enzyme inhibitor
biology.protein
Cattle
Specific activity
Ca(2+) Mg(2+)-ATPase
Sodium-Potassium-Exchanging ATPase
medicine.symptom
medicine.drug
Subjects
Details
- ISSN :
- 15577732 and 10807683
- Volume :
- 8
- Database :
- OpenAIRE
- Journal :
- Journal of Ocular Pharmacology and Therapeutics
- Accession number :
- edsair.doi.dedup.....37c12c2c5e39a867ac2a4a4c4c98d78c