Table 3

Antagonist potencies to block 5-HT-stimulated [cAMP]_imediated by the recombinant human 5-HT_7(a) receptor isoform stably expressed in murine fibroblasts

Intrinsic activity	Drug	K_i(nM)^3-b	K_b(nM)	E_max	K_b/K_i
Partial Agonists	1-NP	76	117 ± 32	31 ± 6	1.5
Antagonists	Methiothepin	3.7	7.4 ± 2.5	NIA^3-a	2.00
	Octoclothepin	4.3	8.0 ± 3.5	NIA	1.86
	Dihydroergotamine	9.2	3.7 ± 1.1	NIA	0.40
	d-LSD	6.0	8.0 ± 2.6	NIA	1.33
	Mesulergine	21	8.2 ± 1.6	NIA	0.39
	Metergoline	13	9.5 ± 1.5	NIA	0.73
	Clozapine	69	24 ± 7	NIA	0.35
	Ritanserin	47	66 ± 17	NIA	1.40
	Spiperone	114	59 ± 18	NIA	0.52
	Cyproheptadine	122	99 ± 35	NIA	0.81
	Ketanserin	1177	174 ± 44	NIA	0.15
	Rauwolscine	2819	868 ± 79	NIA	0.31

↵3-a NIA, No positive or negative intrinsic activity observed up to 10 μM.
↵3-b K_b values represent means ± S.E. of three to seven determinations.