Table 2.

Agonist and Antagonist Serotonin 6 and 7 Receptor Ligands

Receptor Type	Nature of Interaction	Action	Examples	Reference
5-HT6R	Agonist	Partial agonist	EMD386088 (20-fold selectivity), E-6801 and E-6837	[82–84]
		Fully agonist	R-13c (50-fold selectivity), EMDT, WAY-466, WAY-208,466, E-6837, WAY-181,187 and LY586713
	Antagonist		Ro 04–6790 (100-fold selectivity)*, SB-271,046 (50-fold selectivity)*, Ro 63–0563 and SB-258,585 (100-fold selectivity), SB-399,885 (200-fold selectivity), SB-699,929, SB-357,134 and SB-399,885 [11C]-GSK215083**, AVN-322, BVT-74,316, PRX-07034, R-1485, SYN-114, SYN-120 and SUVN-502 are under clinical trial phase I AVN-211, SAM-531, SB-742,457 and SGS-518 under clinical trial phase II	[85–89]
5-HT7R	Agonist	Partial agonist	AS-19, MSD-5a and LP-44 (are selective agonists)	[26,90,91]
		Fully agonist	5-CT and 8-OH-DPAT (non-selective for 5-HT7 and 1), E-55,888, E-57,431, LP-211, LP-12 are selective agonists of 5-HT7R
	Antagonist		DR-4004 (non-selective), SB-258,719, SB-258,741, SB-269,970, SB-656,104, JNJ-18,038,683 are selective antagonists	[90,92]

Notes: *Orally active because of poor capacity to cross blood–brain barrier, **Radiolabelled antagonist developed as serotonin 6 receptor tracer.