title: Excitatory amino acid receptor binding in hippocampus of gerbils with transient global brain ischemia.
abstract: Binding of a variety of ligands for brain excitatory amino acid receptors was examined in membrane preparations extensively washed and treated with Triton X-100 that were obtained from the hippocampus and cerebral cortex of gerbils that survived for different periods after transient global brain ischemia. Bilateral occlusion of the carotid arteries for 5 min did not affect the binding of [3H](+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imi ne (MK-801) to an open ion channel associated with the N-methyl-D-aspartate (NMDA)-sensitive subclass in both central structures of gerbils that survived for 1 to 4 weeks after the injury when determined at equilibrium in the presence of 3 different endogenous agonists including L-glutamic acid (Glu), glycine (Gly) and spermidine at maximally effective concentrations. In contrast, the ischemic occlusion significantly diminished [3H]MK-801 binding when determined before equilibrium in the presence of the 3 stimulants in hippocampal membranes without altering that in cortical membrane 2 weeks after the insult, so that the initial association rates were invariably reduced by more than 60%. Moreover, the occlusion not only reduced the binding of both [3H]Glu and [3H]D,L-(E)-2-amino-4-propyl-5-phosphono-3-pentenoic acid to the NMDA domain on the NMDA receptor ionophore complex, but also decreased the binding of both [3H]Gly and [3H]5,7-dichlorokynurenic acid to the Gly domain. However, the insult did not induce any detectable changes under the experimental conditions employed in either the binding of [3H]DL-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) to the AMPA-sensitive subclass or the binding of kainic acid (KA) to the KA-sensitive subclass in both central regions of animals that survived for 2 weeks. These results suggest that transient global brain ischemia may predominantly impair neuronal and/or glial cells enriched of the NMDA receptor ionophore complex in gerbil hippocampus.
authors.affiliation: Department of Pharmacology, Setsunan University, Osaka, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yoneda
authors.forename: T
authors.initials: T
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Ogita
authors.forename: T
authors.initials: T
authors.lastname: Katoh
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
authors.forename: Y
authors.initials: Y
authors.lastname: Maruoka
authors.forename: M
authors.initials: M
authors.lastname: Nakamura
mesh_terms: D000818:Animals; D005849:Gerbillinae; D006624:Hippocampus / Q000378:metabolism*; D007473:Ion Channels / Q000378:metabolism; D002546:Ischemic Attack, Transient / Q000378:metabolism*; D008297:Male; D008566:Membranes / Q000378:metabolism; D011869:Radioligand Assay; D017459:Receptors, Amino Acid / Q000378:metabolism*
chemical_list: D007473:Ion Channels; D017459:Receptors, Amino Acid