Table 1.

Ki values (nM) of L-SPD to the human D1, D4 and D5 receptors stably expressed in HEK293 cells and human D2 and D3 receptors stably expressed in CHO cells. Competitive inhibition by L-SPD of ~1nM [³H]SCH23390 binding to D1 and D5 receptors and of ~1nM [³H]methylspiperone binding to D2, D3 and D4 receptors was conducted, and its Ki values were determined. Each value represents mean ± S.E.M. of three experiments.

	D1-like receptors		D2-like receptors
	D1R	D5R	D2R	D3R	D4R
L-SPD	5.6 ± 0.7	18.4 ± 2.5	15.0 ± 1.4	7.8 ± 0.6	>1000