Isolation, Sequencing, Synthesis, and Pharmacological Characterization of Two Brain Neuropeptides That Modulate the Action of Morphine

• Published in: Proceedings of the National Academy of Sciences - PNAS 1985-11, Vol.82 (22), p.7757-7761
• Main Authors: H.-Y. T. Yang, Fratta, W., Majane, E. A., Costa, E.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Analgesia; Animals; Antiserum; Biological and medical sciences; Brain; Brain Chemistry; Cattle; Cell physiology; Chromatography; Fundamental and applied biological sciences. Psychology; Molecular and cellular biology; Morphine; Morphine - pharmacology; Nerve Tissue Proteins - analysis; Nerve Tissue Proteins - isolation & purification; Nerve Tissue Proteins - pharmacology; Neuropeptides; Neurotransmission; Radioimmunoassay; Rats; Rats, Inbred Strains; Species; Ungulates
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.82.22.7757

Two peptides that crossreact with an antiserum raised against Phe-Met-Arg-Phe-NH2were purified from bovine brain extract. Their structures were determined to be Ala-Gly-Glu-Gly-Leu-Ser-Ser-Pro-Phe-Trp-Ser-Leu-Ala-Ala-Pro-Gln-Arg-Phe-NH2and Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2. The sequences were determined by gas-phase sequencing, except for the COOH-terminal phenylalaninamides. These were assigned on the basis of the reactivity of the peptides with the anti-Phe-Met-Arg-Phe-NH2antiserum, which appears to recognize the determinant -Arg-Phe-NH2. Both peptides were synthesized, and the synthetic peptides were found to have the same HPLC retention times as the endogenous Phe-Met- Arg-Phe-NH2-immunoreactive peptides, thus confirming the assignment of phenylalaninamide to the COOH-terminal positions. Both of the synthetic peptides were found to decrease tail-flick latency in rats, and the octapeptide was more active than the octadecapeptide. The octapeptide was found also to attenuate the prolongation of the tail-flick latency induced by morphine.