Table 1

Binding and displacement parameters for rat preparations

	Direct Binding		Displacement
	Nicotine		Cytisine		Ligand	CytisineK_i	Nicotine K_i	dHβEK_i	Ref.^1-a
	B_max	K	B_max	K	Ligand	CytisineK_i	Nicotine K_i	dHβEK_i	Ref.^1-a
	fmol/mg	nM	fmol/mg	nM		nM	nM	nM
Rat brain (P2)	115	0.9	99	0.20	Cytisine	0.14	0.7	17	1
Rat cortex	–	–	4	0.90	Cytisine	0.45	3.3	22	2
Rat cortex	57	3.5	–	–	Nicotine	2.00	4.2	91	3
Rat spinal cord	20	2.2	20	0.40	Cytisine	0.71	2.3	21	4
Rat mean		2.2		0.50		0.83	2.6	38
(S.D.)		(1.1)		(0.29)		(0.71)	(1.3)	(31)
HN42 cells	544	0.40	383	0.12	Cytisine	–	0.43	22
(S.D.)	(117)	(0.01)	(73)	(0.05)				(2)

↵1-a The references are: 1, Anderson and Arneric, 1994; 2,Pabreza et al., 1991; 3, Martino-Barrows and Kellar, 1987; 4, Khan et al., 1994.