SENSITIVITY OF GUINEA-PIG HIPPOCAMPAL GRANULE CELL FIELD POTENTIALS TO HEXOSES INVITRO - AN EFFECT ON CELL EXCITABILITY
SENSITIVITY OF GUINEA-PIG HIPPOCAMPAL GRANULE CELL FIELD POTENTIALS TO HEXOSES INVITRO - AN EFFECT ON CELL EXCITABILITY
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DOI：
10.1113/jphysiol.1984.sp015279
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发表时间：
1984-01-01
影响因子：
5.5
通讯作者：
DROWER, J
中科院分区：
文献类型：
--
作者：
BACHELARD, HS;COX, DWG;DROWER, J
在低糖和另一种糖酵解底物(D-果糖)存在下，研究了豚鼠海马片灌流后诱发颗粒细胞场电位和组织代谢物水平。还考察了葡萄糖类似物(5-硫代-D-葡萄糖、2-脱氧-D-葡萄糖或3-O-甲基-D-葡萄糖)在葡萄糖存在下的作用。葡萄糖或果糖的浓度分别超过2 mM和10 mM，才能维持正常的诱发活动。在5 mM葡萄糖存在下，5-硫代葡萄糖(15 MM)可使群体峰电位幅度降低60%，而对群体兴奋性突触后电位(EPSP)影响不大。除10 mM果糖外，组织中磷酸肌酸和三磷酸腺苷的水平在所有测试条件下基本没有变化。在3-O-甲基葡萄糖、2-脱氧葡萄糖或5-硫代葡萄糖灌流过程中和灌流后，灌流组织乳酸外流速率的降低与场电位衰减的程度呈正相关。在电场衰减的条件下，群体峰电位幅度与EPSP上升速率的关系分析表明，群体峰电位对代谢扰动总是比EPSP更敏感，这表明这对细胞的兴奋性有影响。非氧化葡萄糖代谢的某些方面显然对维持这种颗粒细胞的兴奋性很重要。
Evoked granule cell field potentials and levels of tissue metabolites in superfused guinea-pig hippocampal slices were studied in the presence of low glucose and an alternative glycolytic substrate (D-fructose). The effects of glucose analogs (5-thio-D-glucose, 2-deoxy-D-glucose or 3-O-methyl-D-glucose) in the presence of glucose were also tested. Concentrations of glucose or fructose in excess of 2 mM and 10 mM, respectively, were required to maintain normal evoked activity. 5-Thioglucose (15 mM) in the presence of 5 mM-glucose decreased the amplitude of the population spike by 60% with little effect on population excitatory postsynaptic potential (EPSP). Tissue levels of phosphocreatine and ATP were essentially unchanged under all conditions tested, with the exception of 10 mM-fructose. The decrease in rates of lactate efflux from superfused tissue during and after superfusion with 3-O-methylglucose, 2-deoxyglucose or 5-thioglucose was positively correlated with the extent of attenuation of field potentials. Analysis of the relationship between population spike amplitude and rates of rise of EPSP, under conditions where field potentials were attenuated, showed that the population spike was always more sensitive to metabolic perturbation than was the EPSP, thus indicating an effect on cell excitability. Some aspect of non-oxidative glucose metabolism is apparently important in maintaining this granule cell excitability.