Frog rod outer segments with attached inner segment ellipsoids as an in vitro model for photoreceptors on the retina.
Frog rod outer segments with attached inner segment ellipsoids as an in vitro model for photoreceptors on the retina.
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DOI：
10.1085/jgp.85.1.83
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发表时间：
1985-01
期刊：
影响因子：
--
通讯作者：
Bownds MD
中科院分区：
文献类型：
--
作者：
Biernbaum MS;Bownds MD
可以获得足够用于化学分析的量（0.1 mg/视网膜）的仍然附着于受体细胞（OS-IS）的富含维生素A的内节部分的蛙杆外节的纯化悬浮液。在添加Percoll的含氧葡萄糖-碳酸氢盐林格氏培养基中，它们显示正常的暗电流、光敏感性和光电流动力学数小时。维持两毫摩尔的ATP和GTP的细胞质水平，比孤立的OS高五倍。乌巴因取消暗电流的水平没有改变。核苷三磷酸比在孤立的OS中更有效地缓冲，并且它们的水平在外部钙水平变化期间保持恒定。32 Pi掺入内源性ATP和GTP池的效率是分离OS的两倍，并用于视紫红质的磷酸化。OS-IS通过Na+-、Ca++-和IBMX敏感机制摄取和释放45 Ca ++。光照导致45 Ca ++的释放，这证实了其他小组使用Ca++敏感电极进行的视网膜研究。因此，OS-IS悬浮液模拟了仍然附着在活体视网膜上的光感受器的行为。它们的可用性允许在兴奋和适应过程中发生的电生理和化学变化的同时测定和关联。
Purified suspensions of frog rod outer segments still attached to the mitochondria-rich inner segment portion of the receptor cell (OS-IS) can be obtained in quantities (0.1 mg/retina) sufficient for chemical analysis. In oxygenated glucose-bicarbonate Ringer's medium with added Percoll, they display normal dark currents, light sensitivity, and photocurrent kinetics for several hours. Two millimolar cytoplasmic levels of ATP and GTP are maintained, fivefold higher than in isolated OS. The levels are not altered by abolition of the dark current with ouabain. Nucleoside triphosphates are more effectively buffered than in isolated OS, and their levels remain constant during changes in external calcium levels. 32Pi is incorporated into endogenous ATP and GTP pools twice as efficiently as in isolated OS, and is used in the phosphorylation of rhodopsin. OS-IS take up and release 45Ca++ by Na+-, Ca++-, and IBMX-sensitive mechanisms. Illumination causes release of 45Ca++, which confirms retinal studies by other groups using Ca++- sensitive electrodes. Thus, OS-IS suspensions model the behavior of photoreceptors still attached to the living retina. Their availability permits the simultaneous assay and correlation of electrophysiological and chemical changes occurring during excitation and adaptation.
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DOI：
10.1085/jgp.85.1.107
发表时间：
1985-01
期刊：
The Journal of general physiology
影响因子：
--
作者：
Biernbaum MS;Bownds MD
通讯作者：
Bownds MD
DOI：
10.1085/jgp.58.3.225
发表时间：
1971-09
期刊：
The Journal of general physiology
影响因子：
--
作者：
Bownds D;Gordon-Walker A;Gaide-Huguenin AC;Robinson W
通讯作者：
Robinson W
影响因子：
3.8
作者：
Biernbaum, M S;Bownds, M D
通讯作者：
Bownds, M D
影响因子：
64.8
作者：
GEORGE, JS;HAGINS, WA
通讯作者：
HAGINS, WA
影响因子：
5.5
作者：
LAMB, TD;MCNAUGHTON, PA;YAU, KW
通讯作者：
YAU, KW