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Characterization of G Protein-coupled Receptors by a Fluorescence-based Calcium Mobilization Assay
Published on: July 28, 2014
Further characterization of Helix FMRFamide receptors: kinetics, tissue distribution, and interactions with the
K Payza1, M J Greenberg, D A Price
1Whitney Laboratory, University of Florida, St. Augustine 32086.
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.
