(+)-PD 128907 hydrochloride

(+)-PD 128907 hydrochloride is a selective dopamine D2/D3 receptor agonist, with Kis of 1.7, 0.84 nM for human and rat D3 receptors, 179, 770 n M for human and rat D3 receptors, respectively.

(+)-PD 128907 displaced [3H]spiperone binding from dopamine D3 receptors (Ki human=1.7 nM and rat=0.84 nM) with >100-fold and 900-fold selectivity over the human (Ki=179 nM) and rat (Ki=770 nM) dopamine D2 receptor[1][2].

(+)-PD 128907 significantly decreases dialysate DA levels in D3 knock out mice. The IC25 values are 61 nM and 1327 nM, respectively, for wild type and D3knock out mice. The ratio of the IC25 values shows that (+)-PD 128907 is 22 times more potent in decreasing dialysate DA levels in wild type as compared to mice lacking the D3 receptor. The D3 agonist evokes a dose related decrease in dialysate DA in wild type mice. Post-hoc analysis shows that all doses tested (0.03, 0.1 and 0.3 mg/kg) significantly inhibit dialysate DA. The IC25 values are 0.05 and 0.44 mg/kg for wild type and knock out mice, respectively, indicating that systemically administered (+)-PD 128907 is 9 times more potent in decreasing dialysate DA in the ventral striatum of wild type as compared to D3 knock out mice. Doses of 1 mg/kg or higher of (+)-PD 128907 markedly inhibits dialysate DA in both wild type and D3 knock out mice[3].

[1]. Collins GT, et al. Dopamine agonist-induced yawning in rats: a dopamine D3 receptor-mediated behavior. J Pharmacol Exp Ther. 2005 Jul;314(1):310-9. [2]. Bristow LJ, et al. The behavioural and neurochemical profile of the putative dopamine D3 receptor agonist, (+)-PD 128907, in the rat. Neuropharmacology. 1996 Mar;35(3):285-94. [3]. Zapata A, et al. Selective D3 receptor agonist effects of (+)-PD 128907 on dialysate dopamine at low doses. Neuropharmacology. 2001 Sep;41(3):351-9.