کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9416775 | 1614338 | 2005 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Suppression of potassium channels elicits calcium-dependent plateau potentials in suprachiasmatic neurons of the rat
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کلمات کلیدی
N-methyl-d-glucamineBarium - باریمBrain slices - برش مغزwhole-cell recordings - ضبط کامل سلولExcitable membranes and synaptic transmission - غشاء جذاب و انتقال سیناپسیCalcium channel physiology, pharmacology, and modulation - فیزیولوژی کانال کلسیم، فارماکولوژی و مدولاسیونCalcium channel blockers - مسدود کننده های کانال کلسیمHypothalamus - هیپوتالاموس
موضوعات مرتبط
علوم زیستی و بیوفناوری
علم عصب شناسی
علوم اعصاب (عمومی)
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
By using whole-cell recordings in acute and organotypic hypothalamic slices, we found that following K+ channel blockade, sustained plateau potentials can be elicited by current injection in suprachiasmatic neurons. In an attempt to determine the ionic basis of these potentials, ion-substitution experiments were carried out. It appeared that to generate plateau potentials, calcium influx was required. Plateau potentials were also present when extracellular calcium was replaced by barium, but were independent upon an increase in the intracellular free calcium concentration. Substitution of extracellular sodium by the impermeant cation N-methyl-d-glucamine indicated that sodium influx could also contribute to plateau potentials. To gain some information on the pharmacological profile of the Ca++ channels responsible for plateau potentials, selective blocker of various types of Ca++ channel were tested. Plateau potentials were unaffected by isradipine, an L-type Ca++ channel blocker. However, they were slightly reduced by Ï-conotoxin GVIA and Ï-agatoxin TK, blockers of N-type and P/Q-type Ca++ channels, respectively. These data suggest that R-type Ca++ channels probably play a major role in the genesis of plateau potentials. We speculate that neurotransmitters/neuromodulators capable of reducing or suppressing potassium conductance(s) may elicit a Ca++-dependent plateau potential in suprachiasmatic neurons, thus promoting sustained firing activity and neuropeptide release.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Brain Research - Volume 1036, Issues 1â2, 2 March 2005, Pages 50-59
Journal: Brain Research - Volume 1036, Issues 1â2, 2 March 2005, Pages 50-59
نویسندگان
Patricia M. Pierson, Xinhuai Liu, Mario Raggenbass,