TABLE 1.

Doses (mg/kg) of spiradoline and CP55940 in drug mixtures

	Spiradoline:CP55940 (mg/kg)
	3:1		1:1		1:3
Cycle	Spiradoline	CP55940	Spiradoline	CP55940	Spiradoline	CP55940
Antinociception and body temperature
1	Vehicle	Vehicle	Vehicle	Vehicle	Vehicle	Vehicle
2	1.45	0.016	0.48	0.016	0.48	0.047
3	2.90	0.031	0.97	0.031	0.97	0.094
4	5.81	0.063	1.94	0.063	1.94	0.188
5	11.61	0.125	3.87	0.125	3.87	0.375
6	23.22	0.250	7.74a	0.250a	7.74	0.750
Response rate and urine output
1	Vehicle	Vehicle	Vehicle	Vehicle	Vehicle	Vehicle
2	0.21	0.008	0.07	0.008	0.07	0.024
3	0.41	0.016	0.14	0.016	0.14	0.049
4	0.83	0.033	0.28	0.033	0.28	0.098
5	1.65	0.065	0.55	0.067	0.55	0.220
6	3.30	0.130	1.10b	0.130b	1.10	0.390

^aED₅₀ of drugs given alone for antinociceptive effects (50°C water).

^bED₅₀ of drugs given alone for effects on food-maintained responding.