ISSN:
1432-2013
Keywords:
Glutamic Acid
;
GABA
;
Microelectrophoresis
;
Corpus striatum
;
Neurone Discharges
;
Glutaminsäure
;
GABA
;
Mikroelektrophorese
;
Corpus striatum
;
Neuronentladungen
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary The antagonistic effect of microelectrophoretically applied glutamic acid (Gl) and gamma-amino-butyric-acid (GABA) upon the synaptically induced discharge activity of neurones of the corpus striatum was investigated in unanesthetized rabbits. 1. In the caudate nucleus (NC) only a small number of neurones fired spontaneously, but following application of Gl, many neurones could be activated. In the putamen spontaneous discharge activity was much higher. Electrical stimulation of the thalamus evoked discharge activity in the NC only in some of the neurones. Additional application of Gl however, mostly induced a characteristic discharge pattern, consisting of primary activation (PA), followed by after-discharges after a discharge-free interval. 2. The latency of the PA was shortened from approximately 20 msec (maximum) to about 4–6 msec when increasing doses of Gl were applied. High anionic currents had a similar effect. This “net-latency” points to the activation of an oligosynaptic pathway. The discharge-free interval of about 160–300 msec was shortened to some extent by Gl, but only in some neurones large Gl doses abolished the discharge-free pause completely. It is concluded, that the discharge-free interval represents an inhibitory phase, basing on hyperpolarization. 3. The effects of GABA were antagonistic towards Gl. With submaximal doses of GABA the latency of the PA highly increased. Gl reversed the GABA-inhibition and normalized the latency of the PA. High cationic (hyperpolarizing) currents showed similar effects as GABA. It is concluded that in the Gl/GABA-antagonism depolarization and repolarization of the neuronal membrane is involved.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00363663
Permalink
