کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2840971 1165368 2011 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Potassium fluxes across the blood brain barrier of the cockroach, Periplaneta americana
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک دانش حشره شناسی
پیش نمایش صفحه اول مقاله
Potassium fluxes across the blood brain barrier of the cockroach, Periplaneta americana
چکیده انگلیسی

Potassium fluxes across the blood–brain barrier of the cockroach Periplaneta americana were measured using the scanning ion-selective microelectrode technique. In salines containing 15 mM or 25 mM K+, an efflux of K+ from the ganglia of isolated nerve cords was counterbalanced by an influx across the connectives. Metabolic inhibition with CN− resulted in an increase in K+ efflux across both the ganglia and the connectives. Depletion of K+ by chilling the nerve cords in K+-free saline was associated with subsequent K+ influx across the connectives in K+-replete saline at room temperature. There were dramatic increases in K+ efflux across both ganglia and connectives when the nerve cords were exposed to the pore-forming antibiotic amphotericin B. K+ fluxes across the ventral nerve cord were also altered when paracellular leakage was augmented by transient exposure to 3 M urea. K+ efflux was reduced by the K+ channel blockers Ba2+ and tetraethylammonium or by exposure to Ca2+-free saline and K+ efflux from the ganglia was increased by addition of ouabain to the bathing saline. The results provide direct support for a model proposing that K+ is cycled through a current loop between the ganglia and the connectives and that both the Na+/K+-ATPase and K+ channels are implicated in extracellular K+ homeostasis within the central nervous system.

Figure optionsDownload as PowerPoint slideResearch highlights▶ Patterns and mechanisms of potassium fluxes across the blood–brain barrier of the cockroach were studied. ▶ Fluxes were measured using the scanning ion-selective microelectrode technique. ▶ The results support a model proposing that K+ is cycled between the ganglia and the connectives. ▶ K+ cycling creates a current loop. ▶ Both the Na+/K+-ATPase and K+ channels are implicated in extracellular K+ homeostasis.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Insect Physiology - Volume 57, Issue 1, January 2011, Pages 127–135
نویسندگان
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