Identification of two related pentapeptides from the brain with potent opiate agonist activity

Opioid activity of a peptide, beta-lipotropin-(61-91), derived from beta-lipotropin

The pituitary peptide beta-lipotropin displays essentially no opoid activity in a preparation of guinea pig ileum or in the opiate receptor binding assay. However, a fragment, beta-lipotropin-(61-91), with the enkephalin sequence (Tyr-Gly-Gly-Phe-Met) at its NH2-terminus, has typical opioid effects in these two assays.

Peptides from pigeon cerebrum: two-dimensional fingerprinting and amino acid analysis

The number and heterogeneity of endogenous peptides from pigeon cerebrum were studied by two-dimensional peptide fingerprinting. A highly consistent pattern of 8-9 peptides in the 1000-5000 molecular weight range was obtained from each cerebral sample. Amino acid analysis of the peptide material indicated that 30% of the identified residues were dicarboxylic amino acids and 30% were alphatic amino acids. There was no evidence for the presence of arginine or half-cystine in the peptide fraction.

Recent developments in opiate research and their implications for psychiatry

Considerable progress in opiate research has been made during the last few years regarding the identification and localization of opiate receptors in vitro and in vivo, the analysis of drug-receptor interactions and the characterization of an endogenous ligand of the opiate receptor. There is little evidence that effects induced by chronic exposure to opiates - development of tolerance and dependence -are due to changes in opiate receptor mechanisms; it is supposed that the adaptive changes occur mainly in the chain of events triggered by the drug-receptor interaction. Such changes may be directly or indirectly related to the metabolism of neurotransmitters and/or cyclic nucleotides. The obvious links between physical and psychic equivalents of opiate dependence are discussed. Present data points to the significance of brain stem and limbic structures in both these processes, monoamines probably playing an important role. Relations between psychic manifestations of opiate addiction and mental disorders are pointed out.

Isolation and structure of an untriakontapeptide with opiate activity from camel pituitary glands

The isolation of an untriakontapeptide from camel pituitary extracts has been described. Its structure has been determined and shown to be identical to the sequence of carboxyl-terminal 31 amino acids of ovine beta-lipotropin. The peptide possesses very low lipotropic activity but significant opiate activity.

Neurologically active peptides

This paper reviews recent evidence that a number of small peptides found in the brain are active in the central nervous system and behaviorally. Attention is focused on MSH/ACTH 4-10, alpha- and beta-MSH, and the prohormone beta-LPH, as they produce a syndrome of yawning and stretching. Studies with substance P and mainly with MIF-I are also reviewed. It is shown that substance P is an excitatory transmitter or modulator in the dorsal spinal cord with that MIF-I has antiparkinson properties. It is concluded that many polypeptides have direct actions on the central nervous system independent of their neuroendocrine properties.