A screening library for peptide activated G-protein coupled receptors. 1. The test set.

One subset of the G-protein coupled receptor (GPCR) superfamily is that which is activated by a peptide carrying an obligatory positively charged residue (GPCR-PA(+)). This subclass is exemplified by receptors for melanocortins, GnRH, galanin, MCH, orexin, and some chemokine receptors variously involved in eating disorders, reproductive disorders, pain, narcolepsy, obesity, and inflammation. Using the methods described in this study, a region of chemical property space enriched in GPCR ligands was identified.

Cutting edge: serotonin is a chemotactic factor for eosinophils and functions additively with eotaxin.

Elevated levels of serotonin (5-hydroxytryptamine, 5-HT) are observed in the serum of asthmatics. Herein, we demonstrate that 5-HT functions independently as an eosinophil chemoattractant that acts additively with eotaxin. 5-HT2A receptor antagonists (including MDL-100907 and cyproheptadine (CYP)) were found to inhibit 5-HT-induced, but not eotaxin-induced migration.