EFFECTS OF METABOLIC BLOCKERS ON CA2+-DEPENDENT CURRENTS IN CULTURED SENSORY NEURONS FROM NEONATAL RATS

被引:18
作者
STAPLETON, SR [1 ]
SCOTT, RH [1 ]
BELL, BA [1 ]
机构
[1] ST GEORGE HOSP, SCH MED, DIV CLIN NEUROSCI, LONDON SW17 0RE, ENGLAND
基金
英国惠康基金;
关键词
CULTURED NEURONS; CA2+ CURRENTS; CA2+-ACTIVATED CHLORIDE CURRENTS; INTRACELLULAR CA2+ HOMEOSTASIS; METABOLIC INHIBITION; CYANIDE; 2-DEOXYGLUCOSE; FRUCTOSE 1,6-DIPHOSPHATE;
D O I
10.1111/j.1476-5381.1994.tb14023.x
中图分类号
R9 [药学];
学科分类号
1007 ;
摘要
1 The whole cell variant of the patch clamp technique was used to record high voltage-activated Ca2+ currents and Ca2+-activated Cl- tail currents from cultured neonatal rat dorsal root ganglion neurones. The aim of the project was to use these currents as physiological indices of intracellular Ca2+ regulation under control conditions and in the presence of metabolic inhibitors. 2 Carbonyl cyanide p-trifluoromethoxyphenylhydrazone (5 mu M) and sodium cyanide (1 mu M) inhibited Ca2+ currents within 20 s, even when ATP was present in the patch pipette solution, suggesting a direct action on Ca2+ channels. These metabolic inhibitors did not affect Ca2+ current 'run down' or inactivation kinetics. 3 Cultured neonatal dorsal root ganglion neurones of the rat were relatively insensitive to the removal of glucose and ATP from the recording solutions for up to 3 h. These data suggest that the Ca2+ homeostatic mechanisms in these cells are highly resistant to metabolic insult. 4 However 2-deoxy-D-glucose (5 mM in the extracellular recording medium with no ATP or glucose present did prolong the deactivation time of Ca2+-activated Cl- tail currents and increase the total charge flow following activation of a 500 ms voltage-activated Ca2+ current. This effect was Prevented by inclusion of D-fructose 1,6-diphosphate (500 mu M) in the patch pipette solution. 5 We conclude that some agents used to induce chemical hypoxia, such as carbonyl cyanide p-trifluoromethoxyphenylhydrazone and sodium cyanide, may interact directly with voltage-activated Ca2+ channels and are therefore not appropriate for use in studying disturbed neuronal Ca2+ homeostasis. However, the use of 2-deoxy-D-glucose in the absence of glucose and ATP does represent a model of disturbed Ca2+ homeostasis in cultured dorsal root ganglion neurones. In this study we have combined the whole cell recording technique with cultured neurones under conditions which produce a degree of metabolic stress as reflected by prolonged Ca2+-activated Cl- tail currents. The reduced efficiency of handling of intracellular Ca2+ loads may be an important factor contributing to the onset of neuronal damage during hypoxia and ischaemia.
引用
收藏
页码:57 / 64
页数:8
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