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Titolo:
ENDOGENOUS CALCIUM BUFFERING IN MOTONEURONS OF THE NUCLEUS HYPOGLOSSUS FROM MOUSE
Autore:
LIPS MB; KELLER BU;
Indirizzi:
UNIV GOTTINGEN,ZENTRUM PHYSIOL & PATHOPHYSIOL,HUMBOLDTALLEE 23 D-37073 GOTTINGEN GERMANY UNIV GOTTINGEN,ZENTRUM PHYSIOL & PATHOPHYSIOL D-37073 GOTTINGEN GERMANY
Titolo Testata:
Journal of physiology
fascicolo: 1, volume: 511, anno: 1998,
pagine: 105 - 117
SICI:
0022-3751(1998)511:1<105:ECBIMO>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
AMYOTROPHIC-LATERAL-SCLEROSIS; STEM-SPINAL CORD; BRAIN-STEM; INTRACELLULAR CALCIUM; RESPIRATORY NEURONS; BINDING PROTEINS; CHROMAFFIN CELLS; RAT MOTONEURONS; NERVOUS-SYSTEM; PURKINJE-CELLS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
38
Recensione:
Indirizzi per estratti:
Citazione:
M.B. Lips e B.U. Keller, "ENDOGENOUS CALCIUM BUFFERING IN MOTONEURONS OF THE NUCLEUS HYPOGLOSSUS FROM MOUSE", Journal of physiology, 511(1), 1998, pp. 105-117

Abstract

1. Simultaneous patch clamp and rapid microfluorometric calcium measurements were performed on sixty-five motoneurones in slices of the nucleus hypoglossus in the brainstem of 2- to 6-day-old mice. 2. Hypoglossal motoneurones were particularly vulnerable to mechanical or metabolic stress during isolation of in vitro slice preparations. Therefore, experimental conditions were optimized for functional integrity, as judged by spontaneous rhythmic activity of hypoglossal nerves (XII). 3. Calcium concentrations in the cell soma were monitored with a temporalresolution in the millisecond time domain during depolarizing voltagesteps. Ratiometric fluorescence measurements were made using a rapid monochromator (switching tau < 10 ms), a photomultiplier tube and the calcium sensitive dyes fura-2 and mag-fura-5. 4. Dynamics of somatic calcium transients were investigated as a function of the concentrationof calcium indicator dye in the cell. Decays of calcium transients were approximated to a single exponential component and decay time constants showed a linear dependence on dye concentration. The extrapolateddecay time in the absence of indicator dye was 0.7 +/- 0.2 s, suggesting rapid somatic calcium dynamics under physiological conditions 5. By a process of back-extrapolation, the 'added buffer' method, a calcium binding ratio of 41 +/- 12 (9 cells) was obtained indicating that 98% of the calcium ions entering a hypoglossal motoneurone were bound byendogenous buffers.6. Endogenous calcium binding ratios in hypoglossal motoneurones were small compared with those of other neurones with comparable size or geometry. Accordingly, our measurements suggest thatthe selective vulnerability of hypoglossal motoneurones to calcium-related excitotoxicity might partially result from low concentrations ofcalcium buffers in these cells.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 20/09/20 alle ore 23:02:50