Abstract: The invention provides a peptide capable of blocking voltage-gated K+ channels and inhibiting IL-2 production, which is represented by an amino acid sequence of: Ala-Ser-Cys-Arg-Thr-Pro-Lys-Asp-Cys-Ala-Asp-Pro-Cys-Arg-Lys-Glu-Thr-Gly-Cys-Pro-Tyr-Gly-Lys-Cys-Met-Asn-Arg-Lys-Cys-Lys-Cys-Asn-Arg-Cys; in which the C-terminal is amidated and four disulfide bridges are present in the molecule, and their related peptides isolated from the venom gland of a scorpion Heterometrus spinnifer. The peptides provided by the present invention are neuropeptides which can block voltage-gated K+ channels and inhibit IL-2 production at an extremely low concentration and, therefore, are expected to contribute to application of scorpion toxins to medicines and so on.

Abstract: The present invention provides blockers for glutamate transporters. During a series of syntheses searching for glutamate uptake inhibition in Xenopus oocytes injected with bovine glutamate transporter genes (BGLAST), we obtained .beta.-hydroxyaspartic acid derivatives of the following chemical formula (1): ##STR1## wherein R represents an aromatic acyl group which may be substituted on the ring, a straight or branched lower aliphatic acyl group, an aryl group which may be substituted on the ring, an aralkyl group which may be substituted on the ring, or a straight or branched lower alkyl group; and salts thereof. These compounds are blockers of glutamate transporters, which are useful for the understanding of the function of glutamate transporters and show promise for the treatment of various neurodegenerative diseases.