کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10926374 1091830 2011 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The Ca2+:H+ coupling ratio of the plasma membrane calcium ATPase in neurones is little sensitive to changes in external or internal pH
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی بیولوژی سلول
پیش نمایش صفحه اول مقاله
The Ca2+:H+ coupling ratio of the plasma membrane calcium ATPase in neurones is little sensitive to changes in external or internal pH
چکیده انگلیسی
To explore the effects of both external and internal pH (pHo and pHi) on the coupling between Ca2+ extrusion and H+ uptake by the PMCA activity in snail neurones H+ uptake was assessed by measuring surface pH changes (ΔpHs) with pH-sensitive microelectrodes while Ba2+ or Ca2+ loads were extruded. Ru360 or ruthenium red injection showed that injected Ca2+ was partly taken up by mitochondria, but Ca2+ entering through channels was not. External pH was changed using a mixture of three buffers to minimise changes in buffering power. With depolarisation-induced Ca2+ or Ba2+ loads the ΔpHs were not changed significantly over the pH range 6.5-8.5. With Ca2+ injections into cells with mitochondrial uptake blocked the ΔpHs were significantly smaller at pH 8.5 than at 7.5, but this could be explained in part by the slower rate of activity of the PMCA. Low intracellular pH also changed the ΔpHs responses to Ca2+ injection, but not significantly. Again this may have been due to reduced pump activity at low pHi. I conclude that in snail neurones the PMCA coupling ratio is either insensitive or much less sensitive to pH than in red blood cells or barnacle muscle.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Cell Calcium - Volume 49, Issue 6, June 2011, Pages 357-364
نویسندگان
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