LTP in the dentate gyrus is associated with a persistent NMDA receptor-dependent enhancement of synaptosomal glutamate release.
LTP was induced unilaterally in the dentate gyrus of the anaesthetized rat by tetanic stimulation of the perforant path. Two hours after tetanization synaptosomes were prepared from control and potentiated sides, and the depolarization-induced release of endogenous amino acid neurotransmitters was compared in the two groups, using 4-aminopyridine, potassium or veratridine as depolarizing agents. Glutamate release was greater in synaptosomes from potentiated than control tissue with all three depolarizing agents, but the highest release from control synaptosomes and the most significant enhancement of release from potentiated synaptosomes was seen with veratridine. The tetanus-induced enhancement of veratridine-induced glutamate release was prevented by pretreatment with MK-801. The results indicate that the induction of LTP in the dentate gyrus is accompanied by a persistent enhancement in the ability of synaptosomes to release glutamate in response to a depolarizing stimulus.
Canevari
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L
Division of Neurophysiology and Neuropharmacology, National Institute for Medical Research, Mill Hill, London, UK.
Richter-Levin
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G
Bliss
T V
TV
D015761:4-Aminopyridine / Q000494:pharmacology; D000818:Animals; D016291:Dizocilpine Maleate / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism* / Q000502:physiology; D008297:Male; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000819:agonists* / Q000037:antagonists & inhibitors; D013574:Synaptosomes / Q000378:metabolism*; D014701:Veratridine / Q000494:pharmacology
D016194:Receptors, N-Methyl-D-Aspartate; D018698:Glutamic Acid; D011189:Potassium Chloride; D016291:Dizocilpine Maleate; D014701:Veratridine; D015761:4-Aminopyridine