Article: article from journal or magazin.
Effects of L-cysteine-sulphinate and L-aspartate, mixed excitatory amino acid agonists, on the membrane potential of cat caudate neurons.
Publication types: Journal ArticlePublication Status: ppublish
Responses evoked by L-cysteine-sulphinate (L-CSA) and L-aspartate (L-Asp) were recorded with intracellular electrodes from caudate neurons in halothane anesthetized cats. L-CSA and L-Asp were applied microiontophoretically to caudate cells and their effects on membrane and action potentials, as well as on cortically evoked synaptic potentials were evaluated. L-CSA and L-Asp induced depolarizations accompanied by regular firing resembling kainate (KA)- or quisqualate (QUIS)-induced excitation patterns (type 1) in 82% and 72% of the recorded neurons, respectively, and a mixed pattern consisting of a N-methyl-D-aspartate (NMDA)-like excitation (type 2) followed by a regular type 1 pattern in the remaining cells. In about a quarter of the cells the effects of L-CSA and L-Asp, but not those of KA or QUIS, were partially antagonized by 2-amino-7-phosphonoheptanoate (AP-7), a specific NMDA receptor antagonist. Kynurenate, a broad spectrum excitatory amino acid antagonist, blocked responses elicited by either L-CSA or QUIS. The actions of L-CSA and L-Asp on the firing pattern and membrane potential of cat caudate neurons in situ provide evidence in favor of their mixed agonist nature with respect to NMDA and non-NMDA excitatory amino acid receptors.
2-Amino-5-phosphonovalerate/analogs & derivatives, Action Potentials/drug effects, Amino Acids/pharmacology, Animals, Aspartic Acid/analogs & derivatives, Aspartic Acid/pharmacology, Cats, Caudate Nucleus/drug effects, Caudate Nucleus/physiology, Cysteine/analogs & derivatives, Cysteine/pharmacology, Female, Kainic Acid/pharmacology, Male, Membrane Potentials/drug effects, N-Methylaspartate, Neurotransmitter Agents, Oxadiazoles/pharmacology, Quisqualic Acid
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