Table 4.

Efficacy parameters

Ligand enantiomer	DPAT		5-OH DPAT		6-OH DPAT		7-OH DPAT		8-OH DPAT
	R	S	R	S	R	S	R	S	R	S
Kl/Kh	98.0	25.1	22.2	33.5	29.9	11.7	57.4	17.7	126.1	48.4
Kl/EC50	11.3	5.4	3.2	2.0	6.7	1.2	6.2	1.8	10.7	2.0

K_l/K_h and K_l/EC₅₀ ratios were determined from the data in Tables 1, 2 and 3 as described in the text. K_l was defined using competition versus [³H]-NAD-199, and K_h was derived from the mean of the pK_h and pK_i values derived in competition versus [³H]-NAD-199 and [³H]-8-OH DPAT, respectively.