Evidence that excitatory amino acids not only activate the receptor channel complex but also lead to use-dependent block.
The effects of fast application of excitatory amino acids N-methyl-D-aspartate (NMDA), L-aspartate (ASP), L-glutamate (GLU), quisqualate (QU) and kainate (KAIN) were studied in neurons from the embryonic spinal cord of the chick in monolayer cultures by employing the 'patch clamp' technique in the 'whole cell' mode. It was found that NMDA, ASP, GLU and QU, but not KAIN, induced responses that exhibited several components. The early component decayed with a time constant of 2 s to a lower level of membrane current and discontinuation of the application was followed by an after-current which returned to the base-line with a time constant of about 7 s. It is suggested that NMDA, ASP, GLU and QU, but not KAIN, not only activate the receptor channel complex but also induce use-dependent block.
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L
Vyklický
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L
Vyklický
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F
Vyskocil
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V
Vlachová
E
E
Ujec
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J
Michl
D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D002642:Chick Embryo; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid; D007473:Ion Channels / Q000187:drug effects*; D007608:Kainic Acid / Q000494:pharmacology; D008564:Membrane Potentials; D016202:N-Methylaspartate; D010069:Oxadiazoles / Q000494:pharmacology; D016318:Quisqualic Acid; D017981:Receptors, Neurotransmitter / Q000187:drug effects*; D013116:Spinal Cord / Q000187:drug effects*
D000596:Amino Acids; D005971:Glutamates; D007473:Ion Channels; D010069:Oxadiazoles; D017981:Receptors, Neurotransmitter; D001224:Aspartic Acid; D018698:Glutamic Acid; D016202:N-Methylaspartate; D016318:Quisqualic Acid; D007608:Kainic Acid