. Author manuscript; available in PMC: 2017 Apr 1.

Published in final edited form as: Behav Pharmacol. 2016 Apr;27(2-):155–164. doi: 10.1097/FBP.0000000000000194

Table 2.

ED₅₀s (mg/kg) and dose ratios for the effects of morphine on trial omissions

Monkey		Before daily treatment^a	Daily treatment dose of morphine (mg/kg/day)
Monkey		Before daily treatment^a	0.1	0.32	1.0	3.2	5.6^c	1.0x2^d	3.2x2
AN	ED50	3.7	4.0	7.4	12.4	10.0	7.8		21.1
AN	Dose ratio^b		1.1	2.0	3.3	2.7	2.1		5.6
BR	ED50	2.5	2.9	4.5	4.3	5.6		9.8	8.4
BR	Dose ratio		1.2	1.8	1.7	2.3		4.0	3.4
GE	ED50	4.8	6.7	6.3	5.0	12.8	17.8		38.3
GE	Dose ratio		1.4	1.3	1.0	2.7	3.7		8.0

ED₅₀ values determined prior to daily administration of morphine

Dose ratio (ED₅₀ value during daily treatment divided by the ED₅₀ value before treatment)

Only GE and AN were treated with 5.6 mg/kg once daily

Only BR was treated with 1.0 mg/kg twice daily