L-745870 trihydrochloride

L-745870 trihydrochloride is a potent, selective, brain-penetrant and orally active dopamine D4 receptor antagonist with a Ki of 0.43 nM. L-745870 trihydrochloride shows weaker affinity for D2 (Ki of 960 nM) and D3 (Ki of 2300 nM) receptors, and exhibits moderate affinity for 5-HT2 receptors, sigma sites and α-adrenoceptors[1][2][3].

Signaling Pathways >> GPCR/G Protein >> Dopamine Receptor

Signaling Pathways >> Neuronal Signaling >> Dopamine Receptor

Research Areas >> Neurological Disease

Human D4 Receptor:4.3 nM (Ki)

D2 Receptor:960 nM (Ki)

D3 Receptor:2300 nM (Ki)

L-745870 is capable of antagonizing the ability of D4 receptors to inhibit agonist-induced stimulation of [35S]-GTPgS binding; blocking the inhibition of forskolin-stimulated adenylate cyclase activity in transfected human embryonic kidney (HEK293) and Chinese hamster ovary (CHO) cells; blocking dopamine-induced inhibition of Ca2+ currents in transfected GH4C1 pituitary cells; inhibiting D4 activation of cloned G protein-coupled inwardly rectifying K+ channels; and antagonizing dopamine-induced stimulation of extracellular acidification in transfected cells[1].

L-745870 has good pharmacokinetic properties (20-60% oral bioavailability and plasma t1/2 2.1-2.8 hours) in both rat and monkey, and excellent brain penetration with high brain to plasma ratios in rat[1]. Following oral administration to squirrel monkeys, L745870 (10 mg/kg p.o.) induces mild sedation and extrapyramidal motor symptoms, notably bradykinesia, became apparent at 30 mg/kg. Lower doses of L-745870 has no observable behavioural effects in monkeys[1].

[1]. Bristow LJ, et al. Schizophrenia and L-745,870, a novel dopamine D4 receptor antagonist. Trends Pharmacol Sci. 1997 Jun;18(6):186-8.

[2]. Patel S, et al. Biological profile of L-745,870, a selective antagonist with high affinity for the dopamine D4 receptor. J Pharmacol Exp Ther. 1997 Nov;283(2):636-47.

[3]. Kulagowski JJ, et al. 3-((4-(4-Chlorophenyl)piperazin-1-yl)-methyl)-1H-pyrrolo-2,3-b-pyridine: an antagonist with high affinity and selectivity for the human dopamine D4 receptor. J Med Chem. 1996 May 10;39(10):1941-2.