title: Cross-desensitization Reveals Pharmacological Specificity of Excitatory Amino Acid Receptors in Isolated Hippocampal Neurons.
abstract: Ionic currents elicited by excitatory amino acids were studied, using the concentration clamp method, in enzymatically isolated rat hippocampal neurons. Cross-desensitization between the responses to various agonists was applied to separate the activity of two types of receptors, N-methyl-d-aspartate (NMDA) and non-NMDA. NMDA receptors were selectively activated by NMDA, l- and d-aspartate, d-glutamate and quinolinate. Kainate and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate appeared to be selective, and quisqualate relatively less selective non-NMDA agonists, acting on the same receptor type. l-Glutamate, l- and d-homocysteate activated both receptor types. It is supposed that two receptor sites, activation site and desensitization site, control the action of agonists at the non-NMDA receptor. When examined in the cross-desensitization experiments, NMDA and non-NMDA receptors appear to be represented by the two homogeneous and independent receptor populations operating different ionic channels.
authors.affiliation: A. A. Bogomoletz Institute of Physiology, Ukrainian Academy of Science, Kiev 252024, USSR.
authors.forename: N. I.
authors.initials: NI
authors.lastname: Kiskin
authors.forename: O. A.
authors.initials: OA
authors.lastname: Krishtal
authors.forename: A. Ya.
authors.initials: AY
authors.lastname: Tsyndrenko