کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10926507 1091872 2007 14 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Dynamic and static calcium gradients inside large snail (Helix aspersa) neurones detected with calcium-sensitive microelectrodes
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی بیولوژی سلول
پیش نمایش صفحه اول مقاله
Dynamic and static calcium gradients inside large snail (Helix aspersa) neurones detected with calcium-sensitive microelectrodes
چکیده انگلیسی
We have used quartz Ca2+-sensitive microelectrodes (CASMs) in large voltage-clamped snail neurones to investigate the inward spread of Ca2+ after a brief depolarisation. Both steady state and [Ca2+]i transients changed with depth of penetration. When the CASM tip was within 20 μm of the far side of the cell the [Ca2+]i transient time to peak was 4.4 ± 0.5 s, rising to 14.7 ± 0.7 s at a distance of 80 μm. We estimate that the Ca2+ transients travelled centripetally at an average speed of 6 μm2 s−1 and decreased in size by half over a distance of about 45 μm. Cyclopiazonic acid had little effect on the size and time to peak of Ca2+ transients but slowed their recovery significantly. This suggests that the endoplasmic reticulum curtails rather than reinforces the transients. Injecting the calcium buffer BAPTA made the Ca2+ transients more uniform in size and increased their times to peak and rates of recovery near the membrane. We have developed a computational model for the transients, which includes diffusion, uptake and Ca2+ extrusion. Good fits were obtained with a rather large apparent diffusion coefficient of about 90 ± 20 μm2 s−1.This may assist fast recovery by extrusion.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Cell Calcium - Volume 41, Issue 4, April 2007, Pages 365-378
نویسندگان
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