Table 2. Mean ± SEM number food choices/session, heroin choices/session and heroin intake under various treatment conditions.

T-tests were used to compare data obtained during “Baseline” and “Heroin Withdrawal”. Significant effects of withdrawal were obtained only for Food Choices [t(4)=6.88, p=0.002] and Heroin Choices [t(4)=3.32, p=0.029], and asterisks indicate a significant difference of “Heroin Withdrawal” from “Baseline” (*p<0.05; **p<0.01). T-tests (GNTI) or ANOVAs (other drugs) were used to compare data obtained during treatment with saline and each dose of each test drug during withdrawal. The only significant ANOVA was obtained for Food Choices during treatment with morphine [F(3,9)=16.9, p<0.001]. Crosses indicate significant difference between Food Choices during treatment with saline and different morphine doses as determined by the Dunnett post hoc test (†p<0.05; ††p<0.01).

Treatment Condition	Food Choices	Heroin Choices	Heroin Intake
Baseline	26.5±2.9	16.0±2.3	1.03±0.12
Heroin Withdrawal	1.6±1.4**	26.0±2.9*	0.85±0.17
Morphine + Heroin Withdrawal
Saline	2.0±1.7	26.0±3.8	0.72±0.14
0.032/hr	3.0±2.7	23.8±5.9	1.07±0.15
0.1/hr	18.0±6.3†	20.5±4.7	0.94±0.21
0.32/hr	33.8±2.4††	14.0±2.0	0.97±0.07
Clonidine + Heroin Withdrawal
Saline	2.7±2.2	28.0±4.5	0.59±0.1
0.01/hr	0.3±0.3	14.3±7.3	0.43±0.22
0.032/hr (N=2)	0±0	25±16	0.44±0.11
0.1/hr	0.3±0.3	16.3±8.4	0.71±0.40
Amphetamine + Heroin Withdrawal
Saline	2.7±2.2	30.3±2.2	0.89±0.24
0.032/hr	0±0	16.3±14.7	0.45±0.31
0.1/hr	9.3±9.3	7.3±7.3	0.18±0.18
Antalarmin + Heroin Withdrawal
Saline	2.7±2.2	28.3±4.2	0.81±0.2
1.0/day	3.2±3.3	28.0±6.6	0.95±0.30
3.2/day	6.0±4.6	22.0±2.9	0.76±0.10
10/day	9.3±7.9	20.3±10.1	0.66±0.28
GNTI + Heroin Withdrawal
Saline	2.7±2.2	28.3±4.2	0.81±0.2
1.0	0±0	12±4.9	0.63±0.32