(A) - Amino acid sequence of [desC1, S3, S4]KIIIA[C9A, Aopn4] with disulfide bridge connectivity; (B) - Activity of this analog on neuronal sodium channel subtype Nav1.2; (C) - The on and off rates of this analog on Nav1.2; (D) - Analgesic activity: the cumulative licking time from 0-5 minutes is Phase I (acute), and that from 15-30 minutes is Phase II (inflammatory). Each dose was tested in at least 5 mice. Response to the peptide (dotted line) is compared to the response to saline solution alone (solid line), using Prism Software. (E) - Bar graph of values from panel D. White and black bars represent control and test conditions as do white and black squares in D, respectively. The asterisk indicates that the effect of [desC1, S3, S4]KIIIA[C9A, Aopn4] in the inflammatory phase (phase II) is significantly different from control (p < 0.05).