Functional high- and low affinity agonist binding sites at native dorsal horn AMPA receptors.
Transmission and processing of nociceptive information in the superficial dorsal horn (DH) of the spinal cord involves activation of AMPA-type glutamate receptors (AMPARs). We have studied the properties of native AMPARs in freshly dissociated laminae I-II neurones from postnatal rats using a modified form of the concentration-clamp technique for fast agonist application. Analysis of kainic acid dose-response curves showed the existence of two types of functional agonist binding sites governing AMPAR activation. These sites differ by their affinity for the agonist. Depending on the neurotransmitter concentration reached in the synaptic cleft, the relative contribution of high affinity and low affinity sites might play an important role in the shaping of AMPAR-mediated postsynaptic currents.
Rybalchenko
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Laboratoire de Neurophysiologie cellulaire et intégrée, UMR 7519 CNRS, Université Louis Pasteur, Strasbourg, France.
Schlichter
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R
D000818:Animals; D001665:Binding Sites; D003627:Data Interpretation, Statistical; D004305:Dose-Response Relationship, Drug; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D066298:In Vitro Techniques; D007608:Kainic Acid / Q000494:pharmacology; D007700:Kinetics; D017711:Nonlinear Dynamics; D018408:Patch-Clamp Techniques; D051381:Rats; D018091:Receptors, AMPA / Q000819:agonists* / Q000378:metabolism; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism*
D018690:Excitatory Amino Acid Agonists; D018091:Receptors, AMPA; D007608:Kainic Acid