Background:

Methiothepin mesylate is a potent and non-selective 5-HT2 receptor antagonist, with pKds of 7.10 (5-HT1A), 7.28 (5HT1B), 7.56 (5HT1C), 6.99 (5HT1D), 7.0 (5-HT5A), 7.8 (5-HT5B), 8.74 (5-HT6), and 8.99 (5-HT7), and pKis of 8.50 (5HT2A), 8.68 (5HT2B), and 8.35 (5HT2C).

Methiothepin mesylate is a 5-HT receptor antagonist, with pKds of 7.10, 7.28, 7.56, and 6.99 for 5-HT1A, 5HT1B, 5HT1C, 5HT1D[1]. Methiothepin mesylate also shows pKds of 7.0, 7.8, 8.74, and 8.99 for 5-HT5A, 5-HT5B, 5-HT6, and 5-HT7, respectively[2]. Methiothepin exhibits high affinity at 5-HT2A, 5HT2B, and 5HT2C with pKis of 8.50, 8.68, and 8.35, respectively[3].

[1]. Schoeffter P, et al. 5-Hydroxytryptamine (5-HT)-induced endothelium-dependent relaxation of pig coronary arteries is mediated by 5-HT receptors similar to the 5-HT1D receptor subtype. J Pharmacol Exp Ther. 1990 Jan;252(1):387-95. [2]. Knight AR, et al. Pharmacological characterisation of the agonist radioligand binding site of 5-HT(2A), 5-HT(2B) and 5-HT(2C) receptors. Naunyn Schmiedebergs Arch Pharmacol. 2004 Aug;370(2):114-23. Epub 2004 Jul 30. [3]. Hoyer D, et al. International Union of Pharmacology classification of receptors for 5-hydroxytryptamine (Serotonin). Pharmacol Rev. 1994 Jun;46(2):157-203.