Uperolein, a physalaemin-like endecapeptide derived from the skin of Uperoleia rugosa and Uperoleia marmorata, exhibits spasmodic activity on the gastrointestinal tract and longitudinal muscles [1] [2] [3].

Uperolein, a tachykinin analogue present at concentrations of 10-100 ng/mL, induces or enhances rhythmic contractions and elevates the tone of isolated circular and longitudinal muscular layers throughout the human gastrointestinal tract, ranging from the stomach to the colon [2].

Uperolein, administered intravenously at doses of 0.1 μg/kg and 5 μg/kg as a single injection, demonstrates significant stimulatory effects on the stomach in anesthetized rats, and induces marked spasmogenic responses throughout the entire stomach, from the fundus to the pylorus [3].