Quisqualic acid induced sensitization and the active uptake ofl-quisqualic acid by hippocampal slices
| Autor: | Marvin K. Schulte, James F. Koerner, Robert J. Roon |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
Male
AMPA receptor In Vitro Techniques Hippocampal formation Hippocampus Models Biological Rats Sprague-Dawley chemistry.chemical_compound O-Phthalaldehyde medicine Animals Quisqualic acid Molecular Biology Chromatography High Pressure Liquid Sensitization Aminobutyrates General Neuroscience Glutamate receptor Quisqualic Acid Washout Depolarization Rats Electrophysiology medicine.anatomical_structure 2-Amino-5-phosphonovalerate chemistry Biochemistry Synapses Biophysics Neurology (clinical) 2-Aminoadipic Acid o-Phthalaldehyde Developmental Biology |
| Zdroj: | Brain Research. 605:85-92 |
| ISSN: | 0006-8993 |
| DOI: | 10.1016/0006-8993(93)91359-z |
| Popis: | Hippocampal CA1 pyramidal cell neurons are sensitized to depolarization by L-2-amino-4-phosphonobutanoic acid (L-AP4) following exposure to L-quisqualic acid (QUIS). It has been proposed that induction of this 'QUIS-effect' involves uptake of L-QUIS by hippocampal cells. We have used o-phthaldialdehyde (OPA) derivatization and high performance liquid chromatographic (HPLC) separation of extracts from hippocampal slices which have been exposed to varied concentrations of L-QUIS to investigate L-QUIS uptake into hippocampal slices. We observe uptake rates such that the internal concentration of L-QUIS exceeds the bath concentration within 7 min. The fact that this uptake is concentrative indicates that it is mediated by an active transport system. In addition, uptake of L-QUIS may be linked to the induction of the QUIS-effect. At low concentrations of L-QUIS (< 4 microM), the QUIS-effect is only partially induced within the 4 min incubation time which maximally induces the effect when 16 microM L-QUIS is used. However, repeated 4 min exposure periods of slices to low L-QUIS concentrations will eventually induce the QUIS-effect even when each exposure is separated by extensive washout periods. Hence induction is dependent on both concentration and total exposure time. We also examined the effects of L-alpha-aminoadipic acid and L-serine-O-sulfate on the rate of L-QUIS uptake. Exposure of slices to these compounds prior to treatment with L-QUIS will block the physiological effects of L-QUIS. We found that these 'pre-blocking' compounds did not decrease the rate of L-QUIS uptake.(ABSTRACT TRUNCATED AT 250 WORDS) |
| Databáze: | OpenAIRE |
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