Regulatory volume decrease in frog retinal pigment epithelium

Author:

Adorante J. S.1

Affiliation:

1. Division of Cell and Developmental Biology, University of California,Berkeley 94720.

Abstract

To measure changes in cell water during cell volume regulation, retinal pigment epithelial cells were loaded with tetramethylammonium (TMA). Regulatory volume decrease (RVD) in TMA-loaded retinal pigment epithelial (RPE) cells was measured using double-barreled K(+)-specific microelectrodes. Hyposmotic removal of 12.5 mM NaCl from the apical bath caused bullfrog RPE cells to rapidly swell by approximately 10% and to recover to control level within 10-15 min. Hyposmotic RVD was inhibited by 5 mM basal but not apical BaCl2. Raising K+ in the basal bath from 2 to 12 mM also inhibited RVD. Hyposmotic swelling was accompanied by an increase in the ratio of apical to basolateral membrane resistance (Ra/Rb). The swelling-induced increase in Ra/Rb was inhibited by 5 mM BaCl2. Together, the above findings suggest that hyposmotic swelling enhances basolateral K+ conductance such that K+ and presumably anion efflux mediate net solute and water loss during RVD. RPE cells can also regulate their volume when swollen in isosmotic Ringer solution under certain conditions. When urea or apical HCO3- was used to induce cell swelling, RPE cells underwent an RVD. In contrast, isosmotic elevation of apical K+ from 2 to 5 mM resulted in an increase in RPE cell volume with no subsequent RVD. Thus the method used to swell RPE cells is an important determinant of RVD. Because changes in RPE cell volume in vivo may alter the volume and composition of the extracellular (subretinal) space surrounding the photoreceptors, isosmotic volume regulation may play an important physiological role in maintaining the integrity and health of the neural retina under normal and pathophysiological conditions.

Publisher

American Physiological Society

Subject

Cell Biology,Physiology

Cited by 27 articles. 订阅此论文施引文献 订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3