Effects of the selective metabotropic glutamate receptor agonist, L-CCG-I, on acquisition of a Morris task by rats

Abstract

L-Glutamate, a major excitatory neurotransmitter in the central nervous system, plays an important role in a variety of neuronal events associated with learning and memory, neuronal plasticity, neurotoxicity, and neurodegeneration. We assessed the effects of L-CCG-I ((2S,3S,4S)-alpha-(carboxycyclopropyl)glycine), a conformationally restricted glutamate analogue, in a standard Morris water escape task with young adult rats. L-CCG-I is considered to be a selective agonist of the metabotropic glutamate receptor. Vehicle, 5, 50, or 500 nmol L-CCG-I was injected intra-cerebroventricularly (i.c.v.) into the right lateral ventricle 30 min before the start of each of five daily acquisition sessions. The data indicate that L-CCG-I had a centrally mediated mode of action; rats treated with 500 nmol L-CCG-I were clearly impaired in acquiring the standard Morris water escape task. The no-effect dose was 5 nmol.