Heterogeneous competition of Kv1 channel toxins with kaliotoxin for binding in rat brain: autoradiographic analysis

The α-subunits of Kv1 channels display characteristic distributions and restricted co-assembly in mammalian brain. The heterogeneous composition of Kv1 channels has made it difficult to use specific toxins to label brain structures. We used autoradiography to analyse the competitive behaviour of thr...

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Bibliographic Details
Published in:Neurochemistry international 2004-12, Vol.45 (7), p.1039-1047
Main Authors: Bessone, Richard, Martin-Eauclaire, Marie-France, Crest, Marcel, Mourre, Christiane
Format: Article
Language:English
Subjects:
Animals
Autoradiography
Basal ganglia
Binding
Binding, Competitive
Biological and medical sciences
Brain - metabolism
Central nervous system
Cerebellum
Dendrotoxin
Dose-Response Relationship, Drug
Elapid Venoms - metabolism
Fundamental and applied biological sciences. Psychology
Hippocampus
Kaliotoxin
Life Sciences
Male
Mast cell degranulating peptide
Neocortex
Neurons and Cognition
Neurotoxin
Potassium channel
Potassium Channels - metabolism
Protein Binding - physiology
Rat
Rats
Rats, Sprague-Dawley
Scorpion Venoms - metabolism
Synaptic plasticity
Vertebrates: nervous system and sense organs
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Summary:The α-subunits of Kv1 channels display characteristic distributions and restricted co-assembly in mammalian brain. The heterogeneous composition of Kv1 channels has made it difficult to use specific toxins to label brain structures. We used autoradiography to analyse the competitive behaviour of three Kv1 channel toxins—α-dendrotoxin, kaliotoxin, and mast cell degranulating peptide—for binding to kaliotoxin binding sites in various brain structures. IC 50 varied considerably between brain regions (by up to three orders of magnitude) for each ligand. α-dendrotoxin and kaliotoxin competed equally in some regions and to different extents in others, identifying two types of structure. Mast cell degranulating peptide competed with 125 I -kaliotoxin less efficiently than α-dendrotoxin and kaliotoxin, in all regions. Thus, differences in the capacity of these three toxins to bind to kaliotoxin binding sites provide evidence of major differences in the composition of the Kv1 channels constituting the kaliotoxin binding sites.
ISSN:0197-0186
1872-9754
0197-0186
DOI:10.1016/j.neuint.2004.05.006