A peptide that acts as an N-type calcium channel blocker; binds to human neocortical, rat hippocampal, and chick brain synaptic plasma membranes (IC50s = 4.6, 60, and 150 pM, respectively); blocks norepinephrine and acetylcholine release from human neocortical slices (IC50s = 14 and 3 nM, respectively) and calcium influx into chick synaptosomes by 92% (0.1 μM); blocks electrically-evoked twitch responses of rat vas deferens and guinea pig ileum (IC50s = 9.8 and 55 nM, respectively)