Exposure of hippocampal slices to quisqualate sensitizes synaptic responses to phosphonate-containing analogues of glutamate.
Exposure of transverse slices of rat hippocampus to quisqualate (Quis) resulted in a marked increase in the potency of D- and L-2-amino-4-phosphonobutanoate (APB) and D- and L-2-amino-5-phosphonopentanoate (APV) for depression of extracellular synaptic field potentials recorded from CA1 pyramidal cells. L-APB depressed the amplitude of CA1 field potentials with an IC50 = 1800 microM before exposure to Quis. After a brief (4 min) exposure to sufficient Quis (16 microM) to depress the response by 50%, L-APB depressed these responses with an IC50 = 54 microM. These phosphonate-containing glutamate analogues transiently induced population-spiking after the tissue was pretreated with Quis. This suggests that APB and APV can act as agonists at micromolar concentrations.
D015763:2-Amino-5-phosphonovalerate; D000613:Aminobutyrates / Q000494:pharmacology; D000818:Animals; D005071:Evoked Potentials / Q000187:drug effects; D005971:Glutamates / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D010069:Oxadiazoles / Q000494:pharmacology*; D016318:Quisqualic Acid; D051381:Rats; D011919:Rats, Inbred Strains; D013237:Stereoisomerism; D013569:Synapses / Q000187:drug effects*; D014633:Valine / Q000031:analogs & derivatives / Q000494:pharmacology
D000613:Aminobutyrates; D005971:Glutamates; D010069:Oxadiazoles; D015763:2-Amino-5-phosphonovalerate; D016318:Quisqualic Acid; C012729:2-amino-4-phosphonobutyric acid; D014633:Valine