. 2019 Apr;71(2):225–266. doi: 10.1124/pr.118.017210

TABLE 3.

Effects of μ-opioid agonist analgesics (e.g., morphine) in assays of pain-related CPA

Subject	Pain Stimulus (Time before Conditioning)	Conditioning Sessions		Morphine		Result	Reference
Subject	Pain Stimulus (Time before Conditioning)	#	Duration	Dose (Route)	Time	Result	Reference
			min	mg/kg	min
Rats	Spinal nerve ligation (−3 wk) + von Frey (1/min × 15 min)	10	20 (2/day)	0.3, 3 (s.c.)	−45	Blocked CPA without CPP^a	Hummel et al., 2008
Rats	Intraplantar carrageenan (−4 h) + von Frey (1/min × 15 min)	2	20 (2/day)	0.3, 3 (s.c.)	−45	Blocked CPA without CPP^a	Hummel et al., 2008
Male SD rats	Intraplantar carrageenan (−4 h)	2	40	0.005–10 (i.p.)	−15	Blocked CPA; less potent to produce CPP^a	van der Kam et al., 2008
Male SD rats	Intraplantar CFA (−2 h)	2	30 (2/day)	0.5–1.0 (i.p.)	−30	Blocked CPA without CPP^a	Zhang et al., 2012
Male ICR mice	Intraperitoneal acid (0 min)	2	40 (2/day)	0.1–3.2 (s.c.)	−15	Blocked CPA; less potent to produce CPP^a	Bagdas et al., 2016
Male/female SD rats	Intraplantar formalin (0 min)	2	45	0.5–4.0 (s.c.)	−15	Blocked CPA without CPP^a	Harton et al., 2017
Male/female Fischer 344 rats	Bone cancer (−11 days) + leg movement (0 min)	2	30 (2/day)	75-mg pellet (s.c.)	−1 day	Did not block CPA	Havelin et al., 2017
Male SD rats	Intraplantar formalin (0 min)	2	60 (2/day)	1, 10 nmol (vBNST)	−10 min	Blocked CPA without CPP^a	Maruyama et al., 2018

ICR, Institute of Cancer Research; SD, Sprague-Dawley; vBNST, ventral bed nucleus of the stria terminalis.

^{^a}

These results indicate an antinociceptive drug profile.