Dermorphin Analog, derived from the natural heptapeptide μ-opioid receptor agonist found in amphibian skin, labels m-opioid receptors with high affinity and selectivity in r. The dermorphin-derived peptide [Dmt1] Dermorphin Analog exhibits these properties effectively.
Xenin is a 25 amino acid peptide that has been identified in human gastric mucosa in the search for a counterpart to the amphibian octapeptide xenopsin.