Table 1.

Effects of the CB₁ receptor antagonists rimonabant and AM251, or the endocannabinoid anandamide on the firing activity of DRN 5-HT cells

	Inhibitory effect		Excitatory effect
	Number of sensitive/total cells	Effect in sensitive cells (%)	Number of sensitive/total cells	Effect in sensitive cells (%)
Antagonists
Vehicle (DMSO 0.01%)	5/18	3.1 ± 0.9	5/18	26.2 ± 7.2
Rimonabant 1 µM	9/21	53.1 ± 12.6**	9/21	30.6 ± 5.2
AM251 1 µM	6/12	61.7 ± 15.1*	5/12	16.6 ± 2.4
Endogenous agonists
Vehicle (Tocrisolve 0.07%)	9/34	10.6 ± 2.2	9/34	37.5 ± 7.6
Anandamide 10 µM	24/47†	43.3 ± 7.4**	7/47	22.3 ± 0.7

Data are expressed as mean ± SEM of the percentage of inhibition or excitation induced by the drugs or vehicles in sensitive cells (limits: 25th and 75th percentiles of the vehicle effect).

^*P < 0.05,

^**P < 0.005 compared with the corresponding effect in the vehicle group by the two-sample Student's t-test.

^†P < 0.05 compared with the number of sensitive cells in the vehicle group by the Fischer's exact test.

5-HT, 5-hydroxytryptamine; AM251, N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide; anandamide, N-(2-hydroxyethyl)-5Z,8Z,11Z,14Z-eicosatetraenamide; DMSO, dimethyl sulphoxide; DRN, dorsal raphe nucleus; rimonabant, SR141716A.