PT-141 (Bremelanotide) is a synthetic cyclic heptapeptide originally developed as a metabolite derivative of Melanotan II. It functions as an agonist of the melanocortin receptor system, with preferential activity at MC3R and MC4R subtypes located in the central nervous system. In preclinical laboratory research, PT-141 is utilized to investigate melanocortin receptor pharmacology, particularly the MC4R-mediated signaling pathways within hypothalamic and limbic structures. Experimental models examine receptor-ligand binding kinetics, cAMP generation, and downstream behavioral endpoints in rodent systems. PT-141 is distinguished from other melanocortin agonists by its mechanism of action through central nervous system pathways rather than peripheral vascular mechanisms. Published preclinical studies describe its interaction with dopaminergic and oxytocinergic signaling cascades in hypothalamic nuclei, providing a research tool for dissecting melanocortin-mediated central signaling. Sequence: Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH Molecular Formula: C₅₀H₆₈N₁₄O₁₀ Molecular Weight: 1025.18 g/mol CAS: 189691-06-3 Supplied exclusively for laboratory research purposes. Not for human consumption.