Heterogeneity in use-dependent depression of inhibitory postsynaptic potentials in the rat neostriatum in vitro

被引:9
作者
Radnikow, G [1 ]
Rohrbacher, J [1 ]
Misgeld, U [1 ]
机构
[1] UNIV HEIDELBERG,INST PHYSIOL 1,D-69120 HEIDELBERG,GERMANY
关键词
D O I
10.1152/jn.1997.77.1.427
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
''Minimal stimulation'' was applied to evoke responses in an ''all-or-none'' fashion in presumed medium spiny neurons of rat neostriatal slices in the presence of antagonists for glutamatergic excitation. For comparison, responses were evoked in the same cells by compound stimulation. Bicuculline (30 mu M) blocked responses evoked by minimal stimulation, indicating that they were gamma-aminobutyric acid-A (GABA(A))-receptor-mediated inhibitory postsynaptic potentials (IPSPs), whereas responses evoked by compound stimulation were only reduced in amplitude. Likewise, R(-)baclofen (1-20 mu M) blocked IPSPs evoked by minimal stimulation in all but one cell. On the contrary, responses evoked by compound stimulation were always reduced in amplitude but never blocked. Paired-pulse depression (PPD) of averaged responses to minimal and compound stimulation was observed at a stimulus interval of 300 ms. The GABA(B) receptor antagonist CGP55845A (0.5 mu M) had no effect on PPD evoked by compound stimulation but abolished PPD evoked by minimal stimulation. In a second set of experiments, the two stimulation paradigms were used to evoke responses in neostriatal slices continuously bathed in R(-)baclofen (10-20 mu M). In R(-)baclofen a strong PPD was evoked by minimal and by compound stimulation. The amplitude of the response to compound stimulation increased on application of CGP55845A (0.5 mu M). At the same time, PPD evoked by compound stimulation decreased. On the contrary, IPSP amplitude and PPD evoked by minimal stimulation remained unchanged. We conclude that two types of GABAergic terminals exist in the rat neostriatum, only one of which is regulated by GABA(B) receptors. However, the other class of terminals, not regulated by GABA(B) receptors, displays a much more pronounced PPD.
引用
收藏
页码:427 / 434
页数:8
相关论文
共 42 条
[1]   MULTIPLE GABA(B) RECEPTORS [J].
BONANNO, G ;
RAITERI, M .
TRENDS IN PHARMACOLOGICAL SCIENCES, 1993, 14 (07) :259-261
[2]   INVOLVEMENT OF GABA SYSTEMS IN FEEDBACK-REGULATION OF GLUTAMATE-MEDIATED AND GABA-MEDIATED SYNAPTIC POTENTIALS IN RAT NEOSTRIATUM [J].
CALABRESI, P ;
MERCURI, NB ;
DEMURTAS, M ;
BERNARDI, G .
JOURNAL OF PHYSIOLOGY-LONDON, 1991, 440 :581-599
[3]   Transmitter timecourse in the synaptic cleft: Its role in central synaptic function [J].
Clements, JD .
TRENDS IN NEUROSCIENCES, 1996, 19 (05) :163-171
[4]   GABA-B AUTORECEPTORS REGULATE THE INDUCTION OF LTP [J].
DAVIES, CH ;
STARKEY, SJ ;
POZZA, MF ;
COLLINGRIDGE, GL .
NATURE, 1991, 349 (6310) :609-611
[5]   PAIRED-PULSE DEPRESSION OF MONOSYNAPTIC GABA-MEDIATED INHIBITORY POSTSYNAPTIC RESPONSES IN RAT HIPPOCAMPUS [J].
DAVIES, CH ;
DAVIES, SN ;
COLLINGRIDGE, GL .
JOURNAL OF PHYSIOLOGY-LONDON, 1990, 424 :513-531
[6]   FREQUENCY-DEPENDENT DEPRESSION OF INHIBITION IN GUINEA-PIG NEOCORTEX INVITRO BY GABAB RECEPTOR FEEDBACK ON GABA RELEASE [J].
DEISZ, RA ;
PRINCE, DA .
JOURNAL OF PHYSIOLOGY-LONDON, 1989, 412 :513-541
[7]   STATISTICAL FACTORS INVOLVED IN NEUROMUSCULAR FACILITATION AND DEPRESSION [J].
DELCASTILLO, J ;
KATZ, B .
JOURNAL OF PHYSIOLOGY-LONDON, 1954, 124 (03) :574-585
[8]   QUANTAL ANALYSIS OF INHIBITORY SYNAPTIC TRANSMISSION IN THE DENTATE GYRUS OF RAT HIPPOCAMPAL SLICES - A PATCH-CLAMP STUDY [J].
EDWARDS, FA ;
KONNERTH, A ;
SAKMANN, B ;
BUSCH, C .
JOURNAL OF PHYSIOLOGY-LONDON, 1990, 430 :213-+
[9]  
FROESTL W, 1992, PHARM COMMUN, V2, P52
[10]   GABAB-RECEPTOR-ACTIVATED K+ CURRENT IN VOLTAGE-CLAMPED CA3 PYRAMIDAL CELLS IN HIPPOCAMPAL CULTURES [J].
GAHWILER, BH ;
BROWN, DA .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1985, 82 (05) :1558-1562