A spider toxin, ω-agatoxin IV A, binds to fixed as well as living tissues: cytochemical visualization of P/Q-type calcium channels. (1st September 2016)

• Record Type: Journal Article
• Authors: Nakanishi, Setsuko
• Is Part Of: Microscopy. Volume 65:Number 4(2016:Aug.)
• Page Start: 337
• Page End: 340
• Publication Date: 2016-09-01
• Subjects: ω-agatoxin IV A -- P/Q-type calcium channels -- cytochemical visualization -- fixed brain -- auditory brainstem -- synapse; Microscopy -- Periodicals; 502.825
• DOI: 10.1093/jmicro/dfw013
• Languages: English
• ISSNs: 2050-5698

Abstract

Abstract : ω-Agatoxin IV A, a peptidyl toxin from Agelenopsis aperta venom, selectively binds to voltage-gated P/Q-type calcium channels. ω-Agatoxin IV A has been used as a selective tool in pharmacological and electrophysiological studies. Visualization of P/Q-type calcium channels has previously been accomplished using biotin-conjugated ω-Agatoxin IV A in freshly prepared mouse cerebellar and hippocampal slices (Nakanishi et al ., J. Neurosci. Res., 41, 532, 1995). Here biotinylated ω-agatoxin IV A was applied to transcardially fixed brain slices prepared with various fixatives. ω-Agatoxin IV A did not bind to fixed tissues from P/Q-type calcium channel knockout mice, confirming that binding to normal, fixed tissues was not an artifact. Using transmission electron microscopy, locations of biotinylated ω-agatoxin IV A binding sites visualized with gold-conjugated streptavidin showed a similar pattern to those visualized with antibody. The ability of biotinylated ω-agatoxin IV A to bind to fixed tissue provides a new cytochemical technique to study molecular architecture of synapses.