HUMAN 5-HT1F RECEPTOR-STIMULATED [S-35] GTP-GAMMA-S BINDING - CORRELATION WITH INHIBITION OF GUINEA-PIG DURAL PLASMA-PROTEIN EXTRAVASATION

To determine the potency and efficacy of 5-HT1F receptor ligands, a [S -35]GTP gamma S binding assay was developed and optimized for the huma n 5-HT1F receptor. Compounds which are known to be effective in the ab ortive treatment of migraine were tested for efficacy and potency in t his assay. Naratriptan, sumatriptan, zolmitriptan, and rizatriptan all had agonist activity. The 5-HT1F receptor ligand LY334370 (1-methyl-4 -piperidinyl)-1H-indol-5-yl]-benzamide) was the most potent compound t ested with an EC50 of 2.13 +/- 0.15 nM. LY302148 -1H-pyrazol-4-yl)ethy l]-4-piperidinyl]-1H-indole), methysergide, LY306258 (3-dimethylamino- 2,3,4,9-tetrahydro- 1H-carbazol-6-ol), dihydroergotamine (DHE), L-694, 247 and CP-122,288 were also investigated for potency and efficacy. Th ere was a statistically significant correlation between the pEC(50) fo r the stimulation of [S-35]GTP gamma S binding and the pID(50) for the inhibition of trigeminal nerve-stimulated dural plasma protein extrav asation in the guinea pig. In the course of these studies, it was foun d that the purportedly selective 5-HT1D receptor antagonist GR127935 i nhibited 5-HT1F receptor-stimulated [S-35]GTP gamma S binding with a K -i of 39.6 +/- 9.5 nM. These studies demonstrate that 5-HT1F receptor- mediated stimulation of [S-35]GTP gamma S binding in a clonal cell sys tem is a reproducible, high throughput assay that is predictive of an in vivo model of 5-HT1F receptor activation. (C) 1998 Elsevier Science B.V. All rights reserved.