Publication Date:
1989-05-05
Description:
Activity-dependent variations in extracellular potassium concentration in the central nervous system may be regulated, in part, by potassium spatial buffering currents in glial cells. The role of spatial buffering in the retina was assessed by measuring light-evoked potassium changes in amphibian eyecups. The amplitude of potassium increases in the vitreous humor was reduced to approximately 10 percent by 50 micromolar barium, while potassium increases in the inner plexiform layer were largely unchanged. The decrease in the vitreal potassium response was accurately simulated with a numerical model of potassium current flow through Muller cells, the principal glial cells of the retina. Barium also substantially increased the input resistance of Muller cells and blocked the Muller cell-generated M-wave, indicating that barium blocks the potassium channels of Muller cells. Thus, after a light-evoked potassium increase within the retina, there is a substantial transfer of potassium from the retina to the vitreous humor by potassium current flow through Muller cells.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2562506/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2562506/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Karwoski, C J -- Lu, H K -- Newman, E A -- EY 03526/EY/NEI NIH HHS/ -- EY 04077/EY/NEI NIH HHS/ -- R01 EY004077/EY/NEI NIH HHS/ -- R01 EY004077-19/EY/NEI NIH HHS/ -- New York, N.Y. -- Science. 1989 May 5;244(4904):578-80.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Psychology, University of Georgia, Athens 30602.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2785716" target="_blank"〉PubMed〈/a〉
Keywords:
Ambystoma
;
Animals
;
Barium/pharmacology
;
Electric Conductivity
;
*Light
;
Necturus maculosus
;
Neuroglia/drug effects/*metabolism/radiation effects
;
Potassium/*metabolism
;
Potassium Channels/physiology
;
Rana pipiens
;
Retina/*cytology
;
Vitreous Body/metabolism
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
