Ziconotide (trifluoroacetate salt)

Ziconotide is a synthetic version of ω-conopeptide MVIIA, a peptide toxin originally found in the venom of the fish-eating marine snail C. magus, that blocks N-type calcium channels in rat brain membranes (Kds = 1.1-18 pM; IC50s = 2-55 pM)., It blocks high-voltage-activated calcium currents in rat superior cervical ganglion neurons (IC50 = 32 nM) as well as depolarization-induced norepinephrine release by rat peripheral sympathetic efferent neurons and in rat hippocampus (IC50s = 1.2 and 5.5 nM, respectively). Intrathecal administration of ziconotide inhibits formalin-induced flinch responses and increases the paw withdrawal threshold in the paw pressure test in rats (ED50s = 0.11 and 0.60 μg, respectively), indicating antinociceptive effects. It decreases latency to tail withdrawal in a hot plate test in a rat model of sciatic chronic constriction injury. Ziconotide also reduces infarct volume post ischemia in a rat model of transient focal ischemia.