Bemesetron (MDL 72222) is a selective 5-HT3 receptor antagonist with an IC50 of 0.33 nM[1]. Neuroprotective effect[2].
Blockade of 5-HT3 receptor with Bemesetron (MDL7222) reduces hydrogen peroxide-induced neurotoxicity in cultured rat cortical cells. Bemesetron (0.01, 0.1 and 1 μM, 15 hours) and Y25130 (0.05, 0.5 and 5 μM) concentration-dependently reduce the H2O2-induced decrease of MTT reduction showing 74.9±2.4 and 79.0 ±2.5% with 1 μM and 5 μM, respectively, which are maximal effects[2]. Pretreatment (20 minutes) with Bemesetron (1 μM), Y25130 (5 μM) or MK-801 (10 μM) significantly, but not completely, inhibits the H2O2-induced elevation of [Ca2+]c[2]. Bemesetron (1 μM, 15 hours) significantly blocks the H2O2-induced increase of caspase-3 immunoreactivity[2].
Bemesetron (0.1, 1 and 10 mg/kg; i.p.) is used in male adult albino mice. The lowest dose do not cause any significant change in catalepsy. However, Bemesetron (1 mg/kg) causes a significant reduction of catalepsy (from 90 min after Haloperidol), while 10 mg/kg significantly potentiates the phenomenon (from 60 min after Haloperidol). The maximum inhibition of catalepsy (about 75%) occurs at 120 min, and the maximum potentiation (about 4.5-times the control value) occurs at 60 min after Haloperidol[3].
References:
[1]. Peters JA, et al. An electrophysiological investigation of the properties of 5-HT3 receptors of rabbit nodose ganglion neurones in culture. Br J Pharmacol. 1993 Oct;110(2):665-76.
[2]. Lee HJ, et al. Blockade of 5-HT(3) receptor with MDL7222 and Y25130 reduces hydrogen peroxide-induced neurotoxicity in cultured rat cortical cells. Life Sci. 2005 Dec 5;78(3):294-300.
[3]. Silva SR, et al. Effects of 5-HT3 receptor antagonists on neuroleptic-induced catalepsy in mice. Neuropharmacology. 1995 Jan;34(1):97-9.