Overview
- Rosso, J.P. et al. (2015) Proc. Natl. Acad. Sci. U.S.A. 112, E891.
Alomone Labs MmTx1 Toxin (200 nM) 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 100 nM Muscimol hydrobromide (#M-240) applications (black bars), and modulated by co-application of 200 nM MmTx1 Toxin (#STM-550), as indicated (green bar). A significant modulation of receptor desensitization and reactivation rates is observed. B. Superimposed traces of GABA(A) receptor currents upon application of 100 nM Muscimol (black) or co-application of 100 nM Muscimol and 200 nM MmTx1 Toxin (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 and tightly binds to these receptors at subnanomolar concentrations. MmTx1 allosterically increases GABA(A) receptor susceptibility to agonistic actions, thereby modulating 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.
