μ Opioid Receptor/MOR Ligand

Sialorphin TFA is a neutral endopeptidase (NEP) and aminopeptidase N (APN) inhibitor that responds to androgen signals. Sialorphin TFA blocks the degradation of endogenous opioid peptides and interacts with μ-, δ-, κ-opioid receptors. Sialorphin TFA regulates the ERK/mTOR signaling pathway by inducing cell cycle arrest, enhancing ERK1/2 activity, and reducing the phosphorylation levels of mTOR, 4E-BP1, p70S6K; accordingly, Sialorphin TFA exhibits antiproliferative activity against colorectal cancer, glioma and prostate cancer cells without cytotoxicity. In addition, Sialorphin TFA also produces antinociceptive responses, regulates sexual behavior, relaxes corpus cavernosum smooth muscle, and alleviates experimental colitis. Sialorphin TFA is also a copper (II) ion-binding ligand. Sialorphin TFA has been used in mechanistic studies related to cancer, pain management and inflammatory bowel disease.

Tyr-Ala-N-(1,3-dimethylbutyl)glycinamide is a μ/δ opioid receptor ligand with high μ opioid receptor selectivity and agonist activity. Tyr-Ala-N-(1,3-dimethylbutyl)glycinamide has an IC₅₀ of 237 nM for μ receptors and 1050 nM for δ receptors. Tyr-Ala-N-(1,3-dimethylbutyl)glycinamide shows K_i values of 17 nM for μ receptors and 480 nM for δ receptors. Tyr-Ala-N-(1,3-dimethylbutyl)glycinamide inhibits electrically evoked contractions of guinea pig ileum and mouse vas deferens. Tyr-Ala-N-(1,3-dimethylbutyl)glycinamide serves as a starting compound for structure-activity relationship investigations of μ receptor recognition.