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Non-N-methyl-D-aspartate receptors mediating synaptic transmission in the avian cochlear nucleus: effects of kynurenic acid, dipicolinic acid and streptomycin.
- Source :
-
Neuroscience [Neuroscience] 1985 Sep; Vol. 16 (1), pp. 171-9. - Publication Year :
- 1985
-
Abstract
- We have examined the effects of a number of excitatory amino acid antagonists on transmission at the cochlear nerve-nucleus magnocellularis synapse in the chicken. Using an in vitro preparation and bath application of drugs, we studied the effects of kynurenic acid and several related substances, streptomycin and a selective N-methyl-D-aspartate receptor antagonist, DL-alpha-aminosuberate. The last compound had no effect on evoked transmission. Of the various kynurenic acid-related compounds tested, only kynurenic and dipicolinic acid selectively altered responses in nucleus magnocellularis. Quinolinic acid, a kynurenic acid analogue that is structurally akin to dipicolinic acid but which acts selectively at N-methyl-D-aspartate receptors, was without effect. The effect of kynurenic acid was solely inhibitory, completely blocking postsynaptic responses with a potency dependent on the frequency of nerve stimulation. No such frequency dependence was seen with dipicolinic acid although this compound also completely suppressed evoked responses. In addition dipicolinic acid potentiated postsynaptic responses at concentrations only slightly lower than those causing inhibition. Streptomycin inhibited responses in nucleus magnocellularis but this effect seems to result partially from the ability of the drug to inhibit presynaptic calcium influx. Our finding that selective antagonists of N-methyl-D-aspartate receptors were ineffective while antagonists of both receptor types, such as kynurenic and dipicolinic acids, inhibited evoked responses reinforces the conclusion that postsynaptic receptors mediating transmission at this synapse are of the non-N-methyl-D-aspartate type [Nemeth et al. (1983) Neurosci. Lett. 40, 39-44].(ABSTRACT TRUNCATED AT 250 WORDS)
- Subjects :
- Animals
Calcium pharmacology
Chickens
Cochlear Nerve cytology
Cochlear Nerve physiology
Culture Techniques
Electric Stimulation
Evoked Potentials drug effects
Kynurenic Acid analogs & derivatives
Neurons drug effects
Receptors, N-Methyl-D-Aspartate
Receptors, Neurotransmitter classification
Receptors, Neurotransmitter drug effects
Streptomycin metabolism
Time Factors
Cochlear Nerve drug effects
Kynurenic Acid pharmacology
Neurons physiology
Picolinic Acids pharmacology
Receptors, Neurotransmitter physiology
Streptomycin pharmacology
Synaptic Transmission drug effects
Subjects
Details
- Language :
- English
- ISSN :
- 0306-4522
- Volume :
- 16
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Neuroscience
- Publication Type :
- Academic Journal
- Accession number :
- 3012407
- Full Text :
- https://doi.org/10.1016/0306-4522(85)90054-5