Overview
- Rosso, J.P. et al. (2015) Proc. Natl. Acad. Sci. U.S.A. 112, E891.
Alomone Labs MmTx1 Toxin-ATTO Fluor-488 labels GABA(A) α1 receptor in rat cerebellum.Rat brain sections were incubated with MmTx1 Toxin-ATTO Fluor-488 (#STM-550-AG) at a concentration of 25 nM. The sections were then incubated with Anti-GABA(A) α1 Receptor (extracellular) Antibody (#AGA-001), followed by donkey anti rabbit labeled with Cy3 (red). A. MmTx1 Toxin-ATTO Fluor-488 binding (green) appears in patches within the granule layer (GL), (arrows). B. GABA(A) α1 receptor immunostaining appears in profiles of GL neurons (arrow). C. Merge of the two images demonstrates variable colocalization. DAPI is used as the counterstain.
Alomone Labs MmTx1 Toxin ATTO-488 binds to rat cerebellum.Rat cerebellum sections were incubated on ice for 2 hours with 30 nM MmTx1 Toxin-ATTO Fluor-488 (#STM-550-AG). Staining (green) was observed mainly in the granule layer (GL) and some labeling in the molecular layer (MOL). DAPI is used as the counterstain (blue). Images were acquired with a 40x objective of a confocal Zeiss LSM 710 microscope.
Alomone Labs MmTx1 Toxin-ATTO Fluor-488 modulates GABA(A) receptors expressed in Xenopus oocytes.A. Representative time course of GABA(A) α1/β2 current activated at a holding potential of -60 mV by 50 nM Muscimol hydrobromide (#M-240) application (black bars), and modulated by co-application of 200 nM MmTx1 Toxin-ATTO Fluor-488 (#STM-550-AG), as indicated (green bar). A significant modulation of receptor desensitization and reactivation rate are observed. B. Superimposed traces of GABA(A) currents upon application of 50 nM Muscimol hydrobromide (black) or co-application of 50 nM Muscimol and 200 nM MmTx1Toxin-ATTO Fluor-488 (green). Taken from the recording in A.
Alomone Labs MmTx1 Toxin-ATTO Fluor-488 modulates GABA(A) receptors expressed in Xenopus oocytes.A. Representative time course of GABA(A) α1/β2 current activated at a holding potential of -80 mV by 50 nM Muscimol hydrobromide (#M-240) application (black bars), and modulated by co-application of 400 nM MmTx1 Toxin-ATTO Fluor-488 (#STM-550-AG), as indicated (green bar). A significant modulation of receptor desensitization and reactivation rate are observed. B. Superimposed traces of GABA(A) currents upon application of 50 nM Muscimol hydrobromide (black) or co-application of 50 nM Muscimol and 400 nM MmTx1 Toxin-ATTO Fluor-488 (green). Taken from the recording in A.
MmTx1 (Micrurotoxin 1) is a peptide toxin originally isolated from Micrurus mipartitus (Red-tailed coral snake) venom. The toxin is an allosteric modulator of γ-aminobutyric acid type A receptors (GABA(A)) and tightly binds to GABA(A) receptors at subnanomolar concentrations. MmTx1 allosterically increases GABA(A) receptor susceptibility to agonistic actions, thereby potentiating receptor opening and desensitization by interacting with the α+/β−interface, a benzodiazepine-like binding site1. MmTx1 may be a priceless tool in evoking seizures for testing novel antiepileptic drugs or as lead molecules for designing therapeutics that modulate GABA(A) receptor activity1.
GABA(A) receptors belong to the cys-loop pentameric ligand-gated ion channel family. These receptors are major inhibitory neurotransmitter receptors in the brain and in the mammalian central nervous system and are responsible for the mediation of GABA action, a major inhibitory neurotransmitter, through the central nervous system2.
