NRA-0160 is a selective dopamine D4 receptor antagonist, with a Ki value of 0.48 nM and with negligible affinity for dopamine D2 receptor (Ki: >10000 nM), D3 receptor (Ki: 39 nM), rat 5-HT2A receptor (Ki: 180 nM) and rat α1 adrenoceptor (Ki: 237 nM).
NRA0160 (0.1, 1, or 3 mg/kg, i.p.) has no effect on PCP-induced hyperlocomotion, stereotypy or ataxia in SD rats. NRA0160, at any dose, does not reduce cumulated counts of locomotion and cumulated scores of stereotypy emerging, and has no effect on extracellular glutamate levels and locomotor activity emerged after saline injection[1]. NRA0160 dose-dependently and significantly reverses the effects of MAP on both A9 and Al0 dopamine neurons. NRA0160 is slightly more potent in reversiig the effects of MAP on A10 (ED50 = 1.0 mg/kg) than on A9 dopamine neurons (ED50 = 1.3 mg/kg). NRA0160 reverses the effect of AP0 on both A9 and A10 dopamine neurons. ED50 values for the effects of NRA0160 on APO-induced inhibition of A9 and A10 dopamine neurons are 1.3 mg/kg and 0.5 mg/kg, respectively[2].
[1]. Abekawa T, et al. Effects of NRA0045, a novel potent antagonist at dopamine D4, 5-HT2A, and alpha1 adrenaline receptors, and NRA0160, a selective D4 receptor antagonist, on phencyclidine-induced behavior and glutamate release in rats. Psychopharmacology (Berl). 2003 Sep;169(3-4):247-56. Epub 2003 Jul 31. [2]. Kawashima N, et al. Effects of selective dopamine D4 receptor blockers, NRA0160 and L-745,870, on A9 and A10 dopamine neurons in rats. Life Sci. 1999;65(24):2561-71.