A polypeptide, a pharmaceutical composition including a polypeptide, and a method for treating a condition using a polypeptide are provided. The polypeptide includes an amino acid sequence according to the general formula X1-X2-X3, wherein X1 and X3 are independently absent or comprise a transduction domain, X2 includes Z3, and Z3 is selected from the group consisting of serine or phosphoserine analogs. The pharmaceutical composition includes a polypeptide including an amino acid sequence according to the general formula X1-X2-X3 and one or more components selected from the group consisting of a pharmaceutically acceptable carrier, a calcium channel blocker, and a combination thereof. X1 and X3 are independently absent or comprise a transduction domain, X2 includes Z3, and Z3 is selected from the group consisting of serine or phosphoserine analogs. The method of treating a condition includes administering a polypeptide including an amino acid sequence according to the general formula X1-X2-X3 to a subject in need thereof, wherein X1 and X3 are independently absent or comprise a transduction domain, X2 includes Z3, and Z3 is selected from the group consisting of serine or phosphoserine analogs. Also provided is a biomedical device including a polypeptide.L'invention concerne un polypeptide, une composition pharmaceutique comprenant un polypeptide, et un procédé de traitement d'une affection à l'aide d'un polypeptide. Le polypeptide comprend une séquence d'acides aminés conforme à la formule générale X1-X2-X3, dans laquelle X1 et X3 sont indépendamment absents ou comprennent un domaine de transduction, X2 comprend Z3, et Z3 est choisi dans le groupe constitué par des analogues de sérine ou de phosphosérine. La composition pharmaceutique comprend un polypeptide comprenant une séquence d'acides aminés selon la formule générale X1-X2-X3 et un ou plusieurs composants choisis dans le groupe constitué par un support pharmaceutiquement acceptable, un agent bloquant les canau
