LY 344864

IC50 Value: 6 nM（Ki） LY344864 is a selective receptor agonist with an affinity of 6 nM (Ki) at the recently cloned 5-HT1F receptor. It possesses little affinity for the 56 other serotonergic and non-serotonergic neuronal binding sites examined [1]. in vitro: he 5-HT1A, 5-HT1B and 5-HT1D receptor agonists 8-OH-DPAT (3 microM), CP93129 (3 microM) and L694247 (3 microM), but not the 5-HT1F receptor agonist LY344864 (1 - 3 microM) inhibited evoked IPSCs [2]. in vivo: After an intravenous dose of 1 mg/kg, rat plasma LY344864 levels declined with time whereas brain cortex levels remained relatively constant for the first 6 hours after injection. Oral and intravenous LY344864 administration potently inhibited dural protein extravasation caused by electrical stimulation of the trigeminal ganglion in rats [1]. Sumatriptan, zolmitriptan, rizatriptan, and naratriptan all contracted the rabbit saphenous vein from baseline tone, whereas LY344864 in concentrations up to 10(-4) M did not contract the rabbit saphenous vein. Furthermore, vascular contractions to sumatriptan were markedly augmented in the presence of prostaglandin F(2alpha) (PGF(2alpha)). However, even in the presence of PGF(2alpha) (3 x 10(-7) M), LY344864 did not contract the rabbit saphenous vein in concentrations well in excess of its 5-HT(1F) receptor affinity (pK(i) = 8.2) [3]. Clinical trial: N/A