Myoactive peptide. Increases the amplitude and frequency of spontaneous contractions and tonus of hindgut muscle. Tachykinin-related peptide 3(3-10) occurs in two forms, Rhopr-TRP-3(3-10) has unmodified Met-9 and Ox-Rhopr-TRP-3(3-10) has oxidation at Met-9. With oxidation at Met-9.