Table 1.

List of structures of select ligands and their known specificity to the various receptors.

Structure	Name	Chemical name	Properties	References
	(R,R′)-Fenoterol (Fen)	5-[(1R)-1-hydroxy-2-{[(2R)-1-(4-hydroxyphenyl) propan-2-yl]amino}ethyl] benzene-1,3-diol	β2-AR agonist Ki = 0.35 and 14.8 μM for β2-AR and β1-AR, respectively	[1]
	(R,R′)-4-methoxy-1-naphthylfenoterol (MNF)	5-[(1R)-1-hydroxy-2-{[(2R)-1-(4-methoxynaphthalen-1-yl)propan-2-yl]amino} ethyl]benzene-1,3-diol	Selective β2-AR agonist Ki = 0.28 and 160.5 μM for β2-AR and β1-AR, respectively	[2]
			Involved in CB receptors signaling	[4]
	AM251	N-(Piperidin-1-yl)-5-(4-iodophenyl)--1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide	Selective CB1 receptor antagonist Ki = 7.5 nM	[20]
			GPR55 agonist EC50 GTPγS = 39 nM	[21]
	rimonabant, SR 141716	N-(Piperidin-1-yl)-5-(4-chloropheny-l)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide	Selective CB1 receptor antagonist Ki = 1.98 nM	[22]
	AM630	6-Iodo-2-methyl-1-[2-(4-morpholinyl-)ethyl]-1H-indol-3-yl](4-methoxy phenyl)methanone	Selective CB2 receptor antagonist Ki = 31.2 nM	[23]
	WIN 55,212-2	(R)-(+)-[2,3-Dihydro-5-methyl-3-(4--morpholinylmethyl) pyrrolo[1,2,3-de]-1,4-benzoxazin--6-yl]-1-naphthalenylmethanone	CB receptor agonist Ki = 62.3 and 3.3 nM for CB1 and CB2 receptors, respectively	[24]
	O-1602	5-Methyl-4-[(1R,6R)-3-methyl-6-(1-c-yclohexen-1-yl]-1,3-benzenediol	Selective GPR55 receptor agonist EC50 GTPγS = 13, > 30000 and > 30000 nM for GPR55, CB1 and CB2 receptors, respectively	[21]
	L-α-Lysophosphatidyl inositol (LPI)	1-Acyl-sn-glycero-3-phospho-(1-D-myo-inositol)	Endogenous GPR55 receptor agonist	[25]
	CP 55,940	(−)-cis-3-[2-Hydroxy-4-(1,1-dimethy-lheptyl)phenyl]-trans-4-(3-hydroxypropyl) cyclohexanol	CB1 and CB2 receptors agonist Ki = 0.6 – 5.0 and 0.7 – 2.6 nM for CB1 and CB2, respectively	[26]
			GPR55 antagonist	[11]