GR113808

GR113808 is an antagonist of the serotonin (5-HT) receptor subtype 5-HT₄.¹ It binds to 5-HT₄ receptors with an IC₅₀ value of 0.4 nM in COS-7 cells expressing the human recombinant receptor and in guinea pig striatal membranes (IC₅₀ = 0.5 nM).² GR113808 is selective for 5-HT₄ receptors over 5-HT₁ receptors (K_is = >10 µM in dog saphenous vein and porcine vena cava), as well as 5-HT₂ and 5-HT₃ receptors (K_is = >10 and 1 μM in rabbit thoracic aorta and rat cerebral cortex, respectively).¹ It is also selective for 5-HT₄ over adenosine, adrenergic, dopamine, GABA, muscarinic, nicotinic, histamine, and NMDA receptors (K_is = >10 μM for all). GR113808 inhibits relaxation induced by 5-HT (Item No. 14332) in rat thoracic esophagus precontracted by carbachol (carbamoylcholine; Item No. 14486; pA₂ = 9.3). In vivo, GR113808 inhibits 5-methoxytryptamine-induced tachycardia in anaesthetized piglets.

WARNING This product is not for human or veterinary use.

1. Gale, J.D., Grossman, C.J., Whitehead, J.W., et al. GR113808: A novel, selective antagonist with high affinity at the 5-HT₄ receptor. Br. J. Pharmacol. 111(1), 332-338 (1994).

2. Van den Wyngaert, I., Gommeren, W., Verhasselt, P., et al. Cloning and expression of a human serotonin 5-HT₄ receptor cDNA. J. Neurochem. 69(5), 1810-1819 (1997).