title: Further characterization of Helix FMRFamide receptors: kinetics, tissue distribution, and interactions with the endogenous heptapeptides.
abstract: The biphasic binding of 125I-daYFnLRFamide to crude brain membranes of Helix aspersa is due to two discernible sites (high and low affinity) rather than different agonist-induced states. The tissues in the snail that show the greatest specific 125I-daYFnLRFamide binding are the brain, reproductive system, and digestive system. The heart shows moderate binding levels, whereas low values are obtained in the oviduct and retractor muscles. The N-terminal SAR of the Helix heptapeptides (X-DPFLRFamide) indicates that, although the substitution of Leu for Met accounts for some, the dipeptide X-Asp produces most of the loss in potency at FMRFamide receptors in Helix brain.
authors.affiliation: Whitney Laboratory, University of Florida, St. Augustine 32086.
authors.forename: K
authors.initials: K
authors.lastname: Payza
authors.forename: M J
authors.initials: MJ
authors.lastname: Greenberg
authors.forename: D A
authors.initials: DA
authors.lastname: Price
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D006372:Helix, Snails / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000378:metabolism*; D009928:Organ Specificity; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018010:Receptors, Invertebrate Peptide; D013329:Structure-Activity Relationship
chemical_list: C055209:FMRFamide receptor; D009842:Oligopeptides; D011956:Receptors, Cell Surface; D018010:Receptors, Invertebrate Peptide