Effects of adenosine on chick retinal pigment epithelium: membrane potentials and light-evoked responses
| Autor: | Futoshi Maruiwa, Nobuhisa Nao-i, Atsushi Sawada, Syuji Nakazaki |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
medicine.medical_specialty
Adenosine Light Vasodilator Agents Biology 4 4'-Diisothiocyanostilbene-2 2'-Disulfonic Acid Membrane Potentials Cellular and Molecular Neuroscience chemistry.chemical_compound Chlorides Chloride Channels Internal medicine medicine Extracellular Electroretinography Animals Pigment Epithelium of Eye Membrane potential Retinal pigment epithelium Cell Membrane Depolarization Retinal Hyperpolarization (biology) Sensory Systems Basal plasma membrane Ophthalmology medicine.anatomical_structure Endocrinology chemistry Biophysics Chickens Microelectrodes Photic Stimulation medicine.drug |
| Zdroj: | Current eye research. 14(8) |
| ISSN: | 0271-3683 |
| Popis: | We examined the effects of adenosine, a putative mediator of neuroprotection during cerebral ischemia, on the electrophysiological characteristics of retina-retinal pigment epithelium-choroid preparations obtained from 1-7 day-old chick and maintained in vitro. Our experiments produced the following results. First, superfusion of the retinal surface with adenosine (0.1 mM) increased the trans-tissue potential. The trans-epithelial (but not the trans-retinal) potential was also increased to the same magnitude with a time-course similar to that of the trans-tissue potential. Second, adenosine produced a depolarization of the epithelial basal plasma membrane with a concomitant decrease in its basal membrane resistance. Third, the trans-epithelial (but not the trans-retinal) c-wave in response to a light stimulus was augmented by adenosine. Adenosine reduced the hyperpolarization of the epithelial basal membrane, but had no effect on the extracellular concentration of K+ in the subretinal region. Fourth, the light-peak that was elicited with a 300 s light stimulus was also depressed by adenosine. Fifth, when 4,4'-diisothiocy anostilbene-2,2'-disulfonate (DIDS), a relatively selective inhibitor of Cl- channels, was perfused at 50 microM on the choroidal surface, adenosine-induced increases in the trans-tissue potential and the c-wave were both abolished. These results suggest that adenosine increased the Cl- conductance of the basal plasma membrane of the retinal pigment epithelium and thereby augmented the standing potential as well as the light-elicited membrane potentials of the retinal pigment epithelium, which seems to be involved in the pathophysiology of retinal ischemia. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|