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          Institute: MPI für medizinische Forschung     Collection: Abteilung Zellphysiologie     Display Documents



ID: 22477.0, MPI für medizinische Forschung / Abteilung Zellphysiologie
Block of native Ca2+ permeable AMPA receptors in rat brain by intracellular polyamines generates double rectification
Translation of Title:Block of native Ca<SUP>2+</SUP> permeable AMPA receptors in rat brain by intracellular polyamines generates double rectification
Authors:Koh, D.-S.; Burnashev, Nail; Jonas, Peter
Language:English
Date of Publication (YYYY-MM-DD):1995
Title of Journal:Journal of Physiology
Journal Abbrev.:J. Physiol.
Volume:486
Issue / Number:2
Start Page:305
End Page:312
Review Status:Peer-review
Audience:Experts Only
Intended Educational Use:No
Abstract / Description:1. The influence of intracellular factors on current rectification of different subtypes of native alpha-amino-3-hydroxy-5-methyl-4- isoxazoleproprionate receptors (AMPARs) was studied in rat brain slices by combining fast application of glutamate with patch pipette perfusion. 2. The peak current-voltage (I-V) relation of the AMPARs expressed in Bergmann glial cells of cerebellum and dentate gyrus (DG) basket cells of hippocampus was weakly rectifying in outside-out patches and nystatin-perforated vesicles, but showed a doubly rectifying shape with a region of reduced slope between 0 and +40 mV in nucleated patches. The I-V relation of AMPARs expressed in hippocampal CA3 pyramidal neurones was linear in all recording configurations. 3. Intracellular application of 25 microM spermine, a naturally occurring polyamine, blocked outward currents in outside-out patches from Bergmann glial cells and DG basket cells in a voltage-dependent manner, generating I-V relations with a doubly rectifying shape which were similar to those recorded in nucleated patches. AMPARs in CA3 pyramidal cell patches were unaffected by 25 microM spermine. 4. The half-maximal blocking concentration of spermine at +40 mV was 0.3 microM in Bergmann glial cell patches and 1.5 microM in DG basket cell patches, whereas it was much higher (>> 100 microM) for CA3 pyramidal cell patches. Spermidine also affected current rectification, but with lower affinity. The block of outward current by polyamines following voltage jumps developed within < 0.5 ms. 5. We conclude that current rectification, rather than being an intrinsic property of the Ca(2+)- permeable AMPAR channel, is generated by polyamine block.
External Publication Status:published
Document Type:Article
Communicated by:Wulf Kaiser
Affiliations:MPI für medizinische Forschung/Abteilung Zellphysiologie/
Identifiers:URI:http://www.jphysiol.org/cgi/content/abstract/486/2... [Abstract]
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