Voltage-gated calcium channel antagonist and method

The present invention relates to a novel class of peptide compounds that specifically block class E voltage-gated calcium channels and to methods for blocking such channels. The invention also, relates to therapeutic treatments, such as treatment of convulsive disorders, using the compounds. A novel class of peptides selectively block class E voltage-gated calcium channels. The class is exemplified by HG peptides such as HG-1, which is isolated from the venom-producing cells of the tarantula Hysterocrates gigas. Also disclosed are methods of producing blocking class E channels using the peptides. HG peptides have utility, for example, in inhibiting oxytocin release and for use as anticonvulsants.