Possible regulation of high-affinity glutamate uptake in synaptosomes of normal and epileptic mice.
Glutamate (Glu) uptake is the primary mechanism for its removal from the synapse. In genetic audiogenic seizures (AGS), Glu uptake is elevated prior to the appearance of seizures. Increased Glu uptake is also observed in synaptosomes from normal mice preincubated with lithium or nitroarginine, an NO synthase inhibitor. Pertussis and cholera toxins cause a marked reduction in Glu uptake. In contrast, neither lithium nor nitroarginine affected Glu uptake by synaptosomes from genetic epileptic mice. Arachidonic acid inhibits Glu uptake, whereas synaptosomes from epileptic mouse brain appear to be more sensitive to arachidonic acid as indicated by a shift of the inhibition curve to the left. These observations are indicative of the possible regulation of Glu uptake by second messengers and its alteration in genetic epilepsy.
Ortiz
J G
JG
Department of Pharmacology, University of Puerto Rico Medical School, San Juan 00936-5067, USA.
Claudio
O
O
Santiago
G
G
Cordero
M L
ML
Nieves
J
J
D000161:Acoustic Stimulation; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D001921:Brain / Q000378:metabolism*; D002772:Cholera Toxin / Q000494:pharmacology; D004827:Epilepsy / Q000235:genetics / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism*; D007700:Kinetics; D008094:Lithium / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D008818:Mice, Neurologic Mutants; D019335:Nitroarginine / Q000494:pharmacology; D012016:Reference Values; D012640:Seizures / Q000235:genetics / Q000378:metabolism*; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D010566:Virulence Factors, Bordetella; D019335:Nitroarginine; D018698:Glutamic Acid; D002772:Cholera Toxin; D008094:Lithium