Excitatory amino acid receptors and synaptic transmission in the rat ventrobasal thalamus.
- 1 October 1987
- journal article
- research article
- Published by Wiley in The Journal of Physiology
- Vol. 391 (1), 499-510
- https://doi.org/10.1113/jphysiol.1987.sp016752
Abstract
1. Extracellular single-neurone recordings were made in the ventrobasal thalamus (v.b.t.) of urethane-anaesthetized rats with multi-barrel ionophoretic electrodes in order to test the hypothesis that excitatory amino acid receptors are involved in the responses of these neurones to stimulation of sensory afferents. 2. Responses of neurones to either physiological stimulation of hair and vibrissa follicle sensory afferents and to ionophoretically applied excitatory amino acids were challenged with the antagonists D-2-amino-5-phosphonovalerate (APV), kynurenate and .gamma.-D-glutamylaminomethyl sulphonate (GAMS). 3. In agreement with previous findings in other brain areas, ionophoretically applied APV was found to selectively antagonize responses of v.b.t. neurones to N-methylaspartate (NMA), whereas GAMS was found to be moderately kainate selective. Kynurenate was found to be relatively non-selective. 4. Responses of neurones to short-duration (10-20 ms) physiological stimulation of afferents were resistant to APV when this antagonist was applied with NMA-selective ionophoretic currents. In contrast, these APV currents were adequate to antagonize responses to maintained physiological stimulation. 5. The broad spectrum excitatory amino acid antagonist kynurenate was found to block synaptic responses of v.b.t. neurones to both short-duration and maintained stimuli when it was applied with currents which were sufficient to reduce responses to ionophoretic quisqualate. 6. GAMS was found to selectively block kainate responses in a proportion of the neurones tested. In such cases, there was little effect on the antagonists on the responses evoked by either short-duration or maintained sensory stimuli. 7. It is concluded that excitatory amino acid receptors of both the NMDA and non-NMDA type are involved in the synaptic responses of v.b.t. neurones to sensory afferent stimulation, and that the apparent synaptic pharmacology depends on the mode of stimulation of the afferent pathway.This publication has 25 references indexed in Scilit:
- Localization of N-acetylaspartylglutamate-like immunoreactivity in selected areas of the rat brainNeuroscience Letters, 1986
- Frequency-dependent involvement of NMDA receptors in the hippocampus: a novel synaptic mechanismNature, 1986
- Evidence for cysteine sulfinate as a neurotransmitterBrain Research, 1982
- The nature of the excitatory transmitter mediating X and Y cell inputs to the cat dorsal lateral geniculate nucleusThe Journal of Physiology, 1982
- Excitatory Amino Acid TransmittersAnnual Review of Pharmacology and Toxicology, 1981
- The structural organization of the ventral posterolateral nucleus in the ratJournal of Comparative Neurology, 1981
- 2-Amino-5-phosphonovalerate (2APV), a potent and selective antagonist of amino acid-induced and synaptic excitationNeuroscience Letters, 1981
- Proceedings: Specificity of nuciferine as an antagonist of amino acid and synaptically evoked activity in cells of the feline thalamus.1975
- Somatotopic organization of vibrissal responses in the ventro‐basal complex of the rat thalamusThe Journal of Physiology, 1973
- The antagonism of the glutamate-induced and synaptic excitations of thalamic neuronesBrain Research, 1972