Instrumental learning within the spinal cord: VI. The NMDA receptor antagonist, AP5, disrupts the acquisition and maintenance of an acquired flexion response

Behav Brain Res. 2004 Oct 5;154(2):431-8. doi: 10.1016/j.bbr.2004.03.030.

Abstract

Prior studies have shown that circuits within the spinal cord can support a simple form of instrumental learning. Spinally transected rats are given shock to one hind leg whenever the leg is extended. This response-outcome contingency causes an increase in flexion duration. The present experiments examine whether the NMDA receptor is involved in the acquisition and maintenance of this instrumental response. Experiment 1 showed that the NMDA receptor antagonist 2-amino-5-phosphonovalerate acid (AP5) reduces instrumental responding in a dose-dependent fashion. Experiment 2 showed that AP5 given after training eliminates the increase in flexion duration. The results implicate the NMDA receptor in the acquisition and maintenance of spinally mediated instrumental behavior.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 2-Amino-5-phosphonovalerate / pharmacology*
  • Analysis of Variance
  • Animals
  • Behavior, Animal
  • Conditioning, Operant / drug effects*
  • Dose-Response Relationship, Drug
  • Dose-Response Relationship, Radiation
  • Electroshock / methods
  • Hindlimb / drug effects
  • Hindlimb / innervation
  • Hindlimb / physiology
  • Injections, Spinal
  • Male
  • Practice, Psychological
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors*
  • Spinal Cord / drug effects*
  • Spinal Cord / physiology
  • Spinal Cord Injuries / physiopathology

Substances

  • Receptors, N-Methyl-D-Aspartate
  • 2-Amino-5-phosphonovalerate