RGD Reference Report - Distinct roles of Kv1 and Kv3 potassium channels at the calyx of Held presynaptic terminal. - Rat Genome Database

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Distinct roles of Kv1 and Kv3 potassium channels at the calyx of Held presynaptic terminal.

Authors: Ishikawa, Taro  Nakamura, Yukihiro  Saitoh, Naoto  Li, Wen-Bin  Iwasaki, Shinichi  Takahashi, Tomoyuki 
Citation: Ishikawa T, etal., J Neurosci. 2003 Nov 12;23(32):10445-53.
RGD ID: 13702408
Pubmed: PMID:14614103   (View Abstract at PubMed)
PMCID: PMC6741004   (View Article at PubMed Central)

Despite identification of >100 potassium channel subunits, relatively little is known about their roles in synaptic transmission. To address this issue we recorded presynaptic potassium currents (IPK) directly from the calyx of Held terminal in brainstem slices of rats. IPK was composed of a 4-aminopyridine (4-AP)-sensitive component and a smaller 4-AP-insensitive component composed of an iberiotoxin-sensitive current and an unidentified slowly activating potassium current. IPK could also be separated into a tetraethylammonium (TEA; 1 mm)-sensitive high-voltage-activated component and a margatoxin (10 nm)-sensitive low-voltage-activated component, which was also blocked by dendrotoxin-I (200 nm) and tityustoxin-Kalpha (100 nm). In outside-out patches excised from calyceal terminals, TEA (1 mm) consistently and to a large extent attenuated IPK, whereas margatoxin attenuated IPK only in a subset of patches (three of seven). Immunocytochemical examination using Kv subtype-specific antibodies indicated that multiple Kv1 and Kv3 subtypes were present at the calyceal terminal. In paired presynaptic and postsynaptic whole-cell recordings, TEA (1 mm) increased both the duration and peak amplitude of presynaptic action potentials and simultaneously potentiated EPSCs. Margatoxin alone had no such effect but reduced the amount of depolarization required for action potential generation, thereby inducing a burst of spikes when the nerve terminal was depolarized for a prolonged period. Thus, at the calyx of Held terminal, Kv3 channels directly regulate evoked transmitter release, whereas Kv1 channels reduce nerve terminal excitability, thereby preventing aberrant transmitter release. We conclude that both Kv3 and Kv1 channels contribute differentially to maintaining the fidelity of synaptic transmission at the calyx of Held.

Gene Ontology Annotations    Click to see Annotation Detail View

Cellular Component

Object SymbolSpeciesTermQualifierEvidenceWithNotesSourceOriginal Reference(s)
Kcna1Ratcalyx of Held is_active_inIDA PMID:14614103SynGO 
Kcna2Ratcalyx of Held is_active_inIDA PMID:14614103SynGO 
Kcna3Ratcalyx of Held is_active_inIDA PMID:14614103SynGO 
Kcnc1Ratcalyx of Held is_active_inIDA PMID:14614103SynGO 
Kcnc4Ratcalyx of Held is_active_inIDA PMID:14614103SynGO 
Kcna1Ratglutamatergic synapse is_active_inIDA PMID:14614103SynGO 
Kcna2Ratglutamatergic synapse is_active_inIDA PMID:14614103SynGO 
Kcna3Ratglutamatergic synapse is_active_inIDA PMID:14614103SynGO 
Kcnc4Ratglutamatergic synapse is_active_inIDA PMID:14614103SynGO 
Kcna1Ratpostsynaptic membrane is_active_inIDA PMID:14614103SynGO 
Kcna2Ratpostsynaptic membrane is_active_inIDA PMID:14614103SynGO 
Kcna3Ratpostsynaptic membrane is_active_inIDA PMID:14614103SynGO 
Kcnc1Ratpostsynaptic membrane is_active_inIDA PMID:14614103SynGO 
Kcnc4Ratpostsynaptic membrane is_active_inIDA PMID:14614103SynGO 
Kcna1Ratpresynaptic membrane is_active_inIDA PMID:14614103SynGO 
Kcna2Ratpresynaptic membrane is_active_inIDA PMID:14614103SynGO 
Kcna3Ratpresynaptic membrane is_active_inIDA PMID:14614103SynGO 
Kcnc1Ratpresynaptic membrane is_active_inIDA PMID:14614103SynGO 
Kcnc4Ratpresynaptic membrane is_active_inIDA PMID:14614103SynGO 

Objects Annotated

Genes (Rattus norvegicus)
Kcna1  (potassium voltage-gated channel subfamily A member 1)
Kcna2  (potassium voltage-gated channel subfamily A member 2)
Kcna3  (potassium voltage-gated channel subfamily A member 3)
Kcnc1  (potassium voltage-gated channel subfamily C member 1)
Kcnc4  (potassium voltage-gated channel subfamily C member 4)

Additional Information