Mechanisms of Ion Transport Across the Mouse Retinal Pigment Epithelium Measured In Vitro
| Autor: | Sighvatur S. Árnason, Thor Eysteinsson, Sunna Bjorg Skarphedinsdottir |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
0301 basic medicine
Physiology and Pharmacology retinal pigment epithelium digestive system Ouabain 03 medical and health sciences chemistry.chemical_compound Mice 0302 clinical medicine medicine Animals Receptor Ion transporter mouse Cells Cultured NaK-ATPase Retinal pigment epithelium Ion Transport Purinergic receptor Sodium Biological Transport Molecular biology Electrophysiology 030104 developmental biology medicine.anatomical_structure chemistry Models Animal Ussing Sodium-Potassium-Exchanging ATPase Adenosine triphosphate 030217 neurology & neurosurgery Bumetanide medicine.drug |
| Zdroj: | Investigative Ophthalmology & Visual Science |
| ISSN: | 1552-5783 0146-0404 |
| Popis: | Purpose To examine ion transport across the mouse retinal pigment epithelium (RPE), measured by the short-circuit current (ISC) and transepithelial resistance (TER). Methods Sheets of RPE from mice (C57BL6/J) with retina, choroid, and sclera attached were mounted in Ussing chambers (0.031-cm2 aperture) and Krebs solution. The ISC and TER were recorded with voltage clamps. Receptors implicated in ion transport were blocked or stimulated by ligands applied to both sides. Results The mean initial ISC was -12.0 ± 3.9 µA/cm2 (basolateral negative), and mean TER was 67.1 ± 8.0 ohm·cm2. RPE preparations remained stable for 3 hours, with ISC decreasing by 0.078 ± 0,033 µA/cm2/hr. Adenosine triphosphate (100 µM) increased ISC by 2.22 ± 0.41 µA/cm2 (P = 0.003). Epinephrine (100 µM) increased ISC by 1.14 ± 0.19 µA/cm2 (P = 0.011). Bumetanide (100 µM) reduced ISC by 1.72 ± 0.73 µA/cm2 (P = 0.027). Ouabain (1 mM) induced a biphasic response: an ISC increase from -7.9 ± 2.4 to -15.49 ± 2.12 µA/cm2 and then a decrease to -3.7 ± 2.2 µA/cm2. Ouabain increased TER by 15.3 ± 4.8 ohm·cm2. These compounds were added sequentially. Apical [K+]o at zero mM transiently increased ISC by 3.36 ± 1.06 µA/cm2. Ba++ decreased ISC from -10.4 ± 3.1 to -6.6 ± 1.8 µA/cm2 (P = 0.01). Ba++ reversed the K+-free response, with Isc decreasing further from -5.65 ± 1.24 to -3.37 ± 0.79 µA/cm2 (P = 0.029). Conclusions The ISC and TER can be recorded from the mouse RPE for 3 hours. Adrenergic and purinergic receptors affect murine RPE ion transport. Sodium-potassium adenosine triphosphatase plays a role in net ion transport across mouse RPE, and Na-K-2Cl cotransporter activity partly accounts for transepithelial ion transport. Mimicking light-induced changes, low subretinal [K+]o increases ion transport transiently, dependent on K+ channels. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|