title: Characterization of NMDA- and AMPA-induced enhancement of AP-1 DNA binding activity in rat cerebellar granule cells.
abstract: Effects of the glutamate receptor agonists, N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), on the activator protein-1 (AP-1) DNA binding activity were studied in primary cultures of rat cerebellar granule cells. Application of NMDA as well as of AMPA produced a concentration-dependent enhancement of AP-1 binding. Further examination revealed that only a brief exposure (10 min) to NMDA or AMPA was required for the initiation of a significant, four- to sixfold enhancement of AP-1 DNA binding activity. Blockade of the desensitization of AMPA receptors by cyclothiazide further reduced the exposure time needed to activate the AP-1 complex. The time needed to achieve a maximal increase of AP-1 binding activity varied depending on the glutamate receptor agonist used. NMDA gave maximal AP-1 stimulation after 60 min exposure, whereas stimulation with AMPA alone reached a maximum after 240 min exposure. When AMPA was applied together with cyclothiazide the maximal enhancement of AP-1 binding was reached much faster, within 120 min. Supershift analysis with specific antibodies against the members of Fos and Jun protein families (c-Fos, Fos B, c-Jun, Jun B, Jun D) revealed that the NMDA-induced AP-1 complex was composed predominantly of Jun D and c-Fos. The composition of the AP-1 complex activated by AMPA alone was similar to that produced by NMDA, but with an additional contribution of Fos B. In contrast, application of AMPA plus cyclothiazide induced an AP-1 transcription with contribution of Jun D, c-Fos, Fos B, c-Jun and Jun B proteins. These findings indicate that glutamate is able to enhance AP-1 DNA binding activity in cerebellar granule cells through both NMDA and AMPA glutamate receptors.
authors.affiliation: Bethune International Peace Hospital, Shijiazhuang, China.
authors.forename: Y N
authors.initials: YN
authors.lastname: Hou
authors.forename: G
authors.initials: G
authors.lastname: Cebers
authors.forename: L
authors.initials: L
authors.lastname: Terenius
authors.forename: S
authors.initials: S
authors.lastname: Liljequist
mesh_terms: D000818:Animals; D001581:Benzothiadiazines / Q000494:pharmacology; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005998:Glycine / Q000494:pharmacology; D007700:Kinetics; D016202:N-Methylaspartate / Q000494:pharmacology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017470:Receptors, Glutamate / Q000502:physiology; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology*
chemical_list: D001581:Benzothiadiazines; D004268:DNA-Binding Proteins; D018691:Excitatory Amino Acid Antagonists; D011810:Quinoxalines; D017470:Receptors, Glutamate; D018808:Transcription Factor AP-1; C062865:2,3-dioxo-6-nitro-7-sulfamoylbenzo(f)quinoxaline; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; C004639:cyclothiazide; D005998:Glycine