title: AMPA receptor mediated behavioral plasticity in the isolated rat spinal cord.
abstract: Previous research has demonstrated that the spinal cord is capable of a simple form of instrumental learning. Spinally transected rats that receive shock to a hind leg in an extended position quickly learn to maintain the leg in a flexed position, reducing net shock exposure whenever that leg is flexed. Subjects that receive shock independent of leg position (uncontrollable shock) do not exhibit an increase in flexion duration and later fail to learn when tested with controllable shock (learning deficit). The present study examined the role of the ionotropic glutamate receptor α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) in spinal learning. Intrathecal application of the AMPA receptor antagonist CNQX disrupted performance of a spinal instrumental learning in a dose dependent fashion (Experiment 1). CNQX also disrupted the maintenance of the instrumental response (Experiment 2) and blocked the induction of the learning deficit (Experiment 3). Intrathecal application of the agonist AMPA had a non-monotonic effect, producing a slight facilitation of performance at a low dose and disrupting learning at a high concentration (Experiment 4). Within the dose range tested, intrathecal application of AMPA did not have a long-term effect (Experiment 5). The results suggest that AMPA-mediated transmission plays an essential role in both instrumental learning and the induction of the learning deficit.
authors.affiliation: Texas A&M University, College Station, TX 77843-4235, United States. Electronic address: hoyaiag@tamu.edu.
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Hoy
authors.affiliation: University of California, San Francisco, CA, United States.
authors.forename: J Russell
authors.initials: JR
authors.lastname: Huie
authors.affiliation: Texas A&M University, College Station, TX 77843-4235, United States.
authors.forename: James W
authors.initials: JW
authors.lastname: Grau
mesh_terms: D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D001522:Behavior, Animal / Q000187:drug effects*; D003216:Conditioning, Operant / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004597:Electroshock; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D066298:In Vitro Techniques; D007858:Learning / Q000187:drug effects; D007859:Learning Disabilities / Q000139:chemically induced / Q000523:psychology; D009473:Neuronal Plasticity / Q000187:drug effects*; D011597:Psychomotor Performance / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000819:agonists / Q000037:antagonists & inhibitors / Q000187:drug effects*; D013116:Spinal Cord / Q000187:drug effects*; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology
chemical_list: D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D018091:Receptors, AMPA; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid