Overview
- Blagbrough, I.S. et al. (1994) Tetra. Lett. 35, 2057.
- Moya, E. et al. (1994) Tetra. Lett. 35, 2061.
- Norris, T.M. et al. (1996) Mol. Pharmacol. 50, 939.
Alomone Labs FTX-3.3 blocks P-type Ca2+ currents in Xenopus oocytes.A. Time course of P-type channel (CaV2.1+α2δ1+β1a) activity before and during applications of 500 mM FTX-3.3 (#F-120), and upon wash. Holding potential was -80 mV and currents were elicited every 10 seconds by 100 ms step to 0 mV. B. Superimposed current traces of P-type channels, before and during applications of 500 μM FTX-3.3 (taken from the experiment described in A).
FTX is a polyamine component of the venom of the American funnel web spider Agelenopsis aperta, and has been described as a selective antagonist of P-type voltage-dependent Ca2+ channels1-2. However, it has been demonstrated that FTX has actions at other sites including NMDA and GABA receptors and also on T-type calcium channels3.
FTX-3.3 (reputed to be structurally identical to the native FTX) has been synthesized4-5 and shown to block P-type calcium channels in rat cerebellar Purkinje cells6. It antagonizes P-, N-, and L-type calcium channels in mammalian Purkinje and superior cervical ganglia neurons with similar potencies; Its IC50 against P-, N-, and L-type channels are ~0.13 mM, ~0.24 mM and ~0.24 mM, respectively7.
FTX-3.3 does not reduce whole-cell sodium current recorded from SK.N.SH cells and is therefore ion selective8.
