The synergism between metabotropic glutamate receptor activation and arachidonic acid on glutamate release is occluded by induction of long-term potentiation in the dentate gyrus

• Published in: Neuroscience 1996-06, Vol.72 (3), p.847-855
• Main Authors: McGahon, B., Lynch, M.A.
• Format: Article
• Language: English
• Subjects: Animals; arachidonic acid; Arachidonic Acid - pharmacology; Biological and medical sciences; Central nervous system; Central neurotransmission. Neuromudulation. Pathways and receptors; dentate gyrus; Dentate Gyrus - drug effects; Dentate Gyrus - metabolism; Fundamental and applied biological sciences. Psychology; glutamate release; Glutamic Acid - metabolism; long-term potentiation (LTP); Male; Membrane Potentials - drug effects; metatotropic glutamate receptor (mG1uR); protein kinase C (PKC); Rats; Rats, Wistar; Receptors, Metabotropic Glutamate - drug effects; Time Factors; Vertebrates: nervous system and sense organs
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/0306-4522(95)00579-X

In synaptosomes prepared from dentate gyrus, activation of the metabotropic glutamate receptor by the specific agonist, trans-1-amino-cyclopentyl-1,3-dicarboxylate, increases release of glutamate in the presence of a low concentration of arachidonic acid. A similar interaction between trans-1-amino-cyclopentyl 1,3-dicarboxylate and arachidonic acid is observed on inositol phospholipid turnover and on protein kinase C activity. We report here that when long-term potentiation is induced in the dentate gyrus by high frequency tetanic stimulation to the perforant path, the synergism between arachidonic acid and trans-1-amino-cyclopentyl-1,3-dicarboxylate is occluded. The occlusion of the synergistic action between arachidonic acid and trans-1-amino-cyclopentyl-1,3-dicarboxylate on glutamate release extended to occlusion of the effect in inositol phospholipid turnover and protein kinase C activation in synaptosomes prepared from dentate gyrus in which long-term potentiation was induced in vivo. One interpretation of the results presented here is that tetanic stimulation is followed by stimulation of metabotropic glutamate receptors at a time when arachidonic acid concentration in the synaptic region is elevated, and that this interaction triggers the presynaptic changes required for expression of long-term potentiation.