کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
9429689 1615203 2005 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Different chloride electrochemical gradients across the plasma membrane in subcellular compartments of rat cerebellum granules
موضوعات مرتبط
علوم زیستی و بیوفناوری علم عصب شناسی علوم اعصاب (عمومی)
پیش نمایش صفحه اول مقاله
Different chloride electrochemical gradients across the plasma membrane in subcellular compartments of rat cerebellum granules
چکیده انگلیسی
The effects of GABA on intracellular Ca2+ have been studied in neonatal rat cerebellum granule cells (CGC) in culture by Oregon Green and two-photon excitation fluorescence microscopy. This technique allowed the study of [Ca2+]i both in cell bodies and neurites. Working with a perfusion chloride concentration corresponding to the average extracellular level, we found that GABA induced an increase in [Ca2+]i in the cell bodies in many of the cells studied with a maximum at day 4 in vitro. This effect disappeared after day 6. However, no increase in [Ca2+]i was ever found in neurites at standard [Cl−]e. On the other hand, an increase of [Ca2+]i was found also in neurites when [Cl−]e was close to zero. The [Ca2+]i increases were blocked by both bicuculline methiodide and nimodipine. The results indicate the presence of an outward directed electrochemical gradient for chloride in the cell bodies which results in depolarization by GABA via GABAA receptor activation. Calcium ion influx ensues due to activation of voltage-gated calcium channels (VGCC). This phenomenon may mediate the well-known trophic effect of GABA on these cells at this developmental stage, via an action of [Ca2+]i on the transcriptional activity of the nucleus. No calcium accumulation takes place in neurites due to either no or a reverse (hyperpolarizing) electrochemical gradient for chloride ions. Such a circumstance in later developmental stages may be of importance for the phasic component of GABA-mediated inhibition.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Neuroscience Letters - Volume 381, Issues 1–2, 10–17 June 2005, Pages 139-143
نویسندگان
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