. Author manuscript; available in PMC: 2013 Sep 16.

Published in final edited form as: Eur J Pharmacol. 2004 Jan 12;483(0):289–293. doi: 10.1016/j.ejphar.2003.10.045

Table 1.

D₅₀ ± S.E.M. values for GHB and haloperidol, given alone and together, to produce catalepsy and to decrease the rate of food-maintained responding in rats (n = 8 per drug or drug combination)

	D₅₀ (mg/kg), i.p.
	Bar test	Hindlimb test	Schedule-controlled responding
GHB	484.8 ± 14.2	546.3 ± 10.2	282.2 ± 15.4
Haloperidol	0.16 ± 0.02	0.21 ± 0.02	0.03 ± 0.00
Predicted	215.0 ± 9.6	240.4 ± 6.1	147.1 ± 2.8
Observed	248.2 ± 7.1	177.7 ± 8.8	147.1 ± 1.2
Predicted/observed	0.87 (NS)	1.35 (NS)	1.00 (NS)

The D₅₀ values observed with the combination of GHB and haloperidol were compared with the values expected from additivity by means of the modified t test described by Tallarida (2000).