Table 4.

Behaviors at baseline, post-morphine, and during withdrawal in P18-21 rats exposed to intermittent or continuous morphine. All data is the average ± SEM (n=4−7/group). Number of line crossing and rearings were counted for 8 minutes at baseline (prior to drug exposure on experimental day 1), post-morphine (1 hour post-morphine on experimental day 1 for IM study, 6 hours post-pump implantation for CM study), and during withdrawal (4 hours post-morphine on experimental day 4 for IM study, 6 hours post-morphine on experimental day 4 for CM study).

	Baseline	Post-Morphine	Withdrawal
Normal Naive
Rearing	7.5 ± 2.4	11.8 ± 4.1	17.2 ± 2.4
Line Crossing	15.8 ± 4.6	19.3 ± 5.3	24.3 ± 1.4

Intermittent Saline
Rearing	1.8 ± 0.6	3.0 ± 0.3	4.0 ± 1.6
Line Crossing	6.2 ± 2.7	11.8 ± 2.0	14.0 ± 2.7
1 mg/kg morphine
Rearing	3.0 ± 0.4	1.0 ± 0.6 ^α	27.8 ± 5.8^**
Line Crossing	4.8 ±0.8	1.4 ± 0.3 ^α	44.3 ± 3.7 ^αα,^***
3 mg/kg morphine
Rearing	3.0 ± 1.0	0.0 ± 0.0 ^α,^*	26.0 ± 4.1^**
Line Crossing	4.0 ± 1.7	0.0 ± 0.0 ^α,^*	41.0 ± 4.0 ^αα,^***

Incision alone
Rearing	19.0 ± 4.7	13.6 ± 5.1	27.7 ± 7.4
Line Crossing	23.3 ± 9.2	23.3 ± 8.7	41.7 ± 5.8
Saline Pump
Rearing	20.5 ± 4.9	22.8 ± 4.6	34.3 ± 10.5
Line Crossing	49.3 ± 3.5	48.5 ± 7.0	42.3 ± 8.8
0.175 mg/kg/h (4.2 mg/kg/day) morphine
Rearing	18.0 ± 2.7	39.3 ± 7.2 ^α,⁺	52.8 ± 14.3
Line Crossing	47.3 ± 6.9	74.5 ± 18.1 ^αα,⁺⁺	65.8 ±13.1 ^αα
0.7 mg/kg/h (16.8 mg/kg/day) morphine
Rearing	21.5 ± 5.1	29.0 ± 8.9 ^α	35.5 ± 6.5
Line Crossing	45.8 ± 5.4	65.3 ± 12.6 ^α	55.5 ± 5.5
1.4 mg/kg/h (33.6 mg/kg/day) morphine
Rearing	12.5 ± 3.8	16.8 ± 6.9	37.0 ± 11.0
Line Crossing	36.8 ± 10.0	61.5 ± 6.3	55.8 ± 6.9
Pellet
Rearing	2.8 ± 1.1	0.0 ± 0.0^*, ^α,⁺	7.0 ± 1.5
Line Crossing	4.4 ±2.5	0.0 ± 0.0^*,^α,⁺	19.8 ± 3.6

^{α, αα}

p<0.05, 0.01 compared to time matched normal naïve rats.

^*,**,***

p<0.05,0.01, 0.001 compared to time matched saline injected/infused animals.

⁺

p<0.05 from time matched incision (no pump) controls.