کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4011213 1602604 2014 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Connexins form functional hemichannels in porcine ciliary epithelium
کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری ایمنی شناسی و میکروب شناسی ایمونولوژی و میکروب شناسی (عمومی)
پیش نمایش صفحه اول مقاله
Connexins form functional hemichannels in porcine ciliary epithelium
چکیده انگلیسی


• Hemichannel function was confirmed in the native porcine nonpigmented epithelium.
• Connexin (Cx) 43 and 50 were localized in the nonpigmented ciliary epithelium (NPE).
• Cx 50 was localized on the basolateral surface of NPE.
• Cx 43 was localized at the apical junction of NPE and pigmented epithelium (PE).
• Cx 43 was localized at the basolateral PE surface, suggesting hemichannel function.

The expression of connexins in the ciliary epithelium is consistent with gap junctions between the pigmented (PE) and nonpigmented ciliary epithelium (NPE) that form when connexon hemichannels from adjacent cells pair to form a channel. Here we present evidence that suggests undocked connexons may form functional hemichannels that permit exchange of substances between NPE and the aqueous humor. Intact porcine eyes were perfused via the ciliary artery and propidium iodide (PI) (MW 668) was added to the aqueous humor compartment as a tracer. After calcium-free solution containing PI was introduced into the aqueous humor compartment for 30 min, fluorescence microscopy revealed PI in the NPE cell layer. PI entry into the NPE was inhibited by calcium and by the connexin antagonist 18α-glycyrrhetinic acid (18-AGA). Studies also were carried out with cultured porcine NPE. Under normal conditions, little PI entered the cultured cells but calcium-free medium stimulated PI accumulation and the entry was inhibited by 18-AGA. In cells loaded with calcein (MW 622), calcium-free solution stimulated calcein exit. 18-AGA partially suppressed calcein exit in calcium-free medium. Connexin 43 and connexin 50 proteins were detected by western blot analysis in both native and cultured NPE. In the intact eye, immunolocalization studies revealed connexin 50 at the basolateral, aqueous humor-facing, margin of the NPE. In contrast, connexin 43 was observed at the junction of the PE and NPE layer and on the basolateral membrane of PE. The results point to functional hemichannels at the NPE basolateral surface. It is feasible that hemichannels might contribute to the transfer of substances between the ciliary epithelium cytoplasm and aqueous humor.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Experimental Eye Research - Volume 118, January 2014, Pages 20–29
نویسندگان
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