DEPLETION OF THE CA++-DEPENDENT RELEASABLE POOL OF GLUTAMATE IN STRIATAL SYNAPTOSOMES ASSOCIATED WITH DENDROTOXIN-INDUCED POTASSIUM CHANNEL BLOCKADE

被引:7
作者
BARBEITO, L [1 ]
SICILIANO, J [1 ]
DAJAS, F [1 ]
机构
[1] FAC MED MONTEVIDEO,DEPT HISTOL,MONTEVIDEO,URUGUAY
关键词
Dendrotoxin; Glutamate release; K[!sup]+[!/sup] channels; synaptosomes;
D O I
10.1007/BF01245118
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
The presynaptic actions of the potassium channel blocker Dendrotoxin (DTX) on the Ca+2-dependent release of endogenous glutamate (GLU) and aspartate (ASP) have been tested in synaptosome-enriched preparations from rat striatum. 24 hours after the intrastriatal administration of DTX the K+-evoked release of GLU and ASP from the striatal synaptosomes was decreased by 40-45%. No changes in the total synaptosomal content of the amino acids were observed. Superfusion of immobilized synaptosomes with DTX or 4-aminopyridine resulted in a dose-dependent increase in the basal outflow of GLU and ASP. The release of GLU stimulated by DTX was Ca+2-dependent and was not abolished by supervising the synaptosomes with 50 μM D-ASP. Moreover, continous superfusion of DTX (7 μM) to synaptosomes almost completely dumped the subsequent release of GLU and ASP stimulated by 20mM K+. It is concluded that blockade of presyanptic K+ channels by DTX leads to a massive release of the transmitter pool of GLU (and possible also ASP) from isolated nerve terminals and to a depletion of the amino acid releasable pool. © 1990 Springer-Verlag.
引用
收藏
页码:167 / 179
页数:13
相关论文
共 25 条
[1]   ACTIVATION OF THE BILATERAL CORTICOSTRIATAL GLUTAMATERGIC PROJECTION BY INFUSION OF GABA INTO THALAMIC MOTOR NUCLEI IN THE CAT - AN INVIVO RELEASE STUDY [J].
BARBEITO, L ;
GIRAULT, JA ;
GODEHEU, G ;
PITTALUGA, A ;
GLOWINSKI, J ;
CHERAMY, A .
NEUROSCIENCE, 1989, 28 (02) :365-374
[2]  
BARBEITO L, 1982, NEUROSCIENCE, V7, P517
[3]  
BARTSCHAT D, 1985, J PHYSL OND, V36, P441
[4]  
BARTSCHAT DK, 1985, J PHYSIOL-LONDON, V361, P419, DOI 10.1113/jphysiol.1985.sp015653
[5]  
BENISHIN CG, 1988, MOL PHARMACOL, V34, P152
[6]  
Dolly J.O., 1987, P81
[7]  
DOLLY JO, 1984, J PHYSIOL-PARIS, V79, P280
[8]   BIOCHEMICAL-EVIDENCE FOR GLUTAMATE AS NEUROTRANSMITTER IN CORTICOSTRIATAL AND CORTICOTHALAMIC FIBERS IN RAT-BRAIN [J].
FONNUM, F ;
STORMMATHISEN, J ;
DIVAC, I .
NEUROSCIENCE, 1981, 6 (05) :863-873
[9]  
GIRAULT JA, 1986, J NEUROCHEM, V47, P98
[10]  
GRAY EG, 1962, J ANAT, V96, P79