Table 1.

Summary of results.

Time	Morphine Sulfate Pellet (25 mg, s.c.)	Osmotic Pump (64 mg/mL, 1.0 μL/hour)	Subcutaneous injection (20 mg/kg, twice daily)
	Plasma Concentration (ng/mL)
24 hours	2695.3±785.1 $	209.7±50.0	N/A
72 hours	1039.5±73.5 $	57.3±39.1	N/A
168 hours	229.5±92.5 $	45.8±25.4	N/A
	Antinociception (tail-flick latency, sec)
24 hours	6.4±0.6 $,#,*	2.5±0.2 #	7.9±0.8 *
72 hours	4.2±0.5 #	3.2±0.2 #	7.1±0.4 *
168 hours	3.2±0.3 #	3.5±0.3 #	5.5±0.2 *
	Naloxone-precipitated withdrawal (number of jumps)
24 hours	61.4±11.7 *	72.0±16.6 *	35.4±5.1
72 hours	130.6±21.8 #,*	107.8±32.2 *	51.8±12.2 *
168 hours	154.2±21.1 $,#,*	84.6±12.6 *	89.6±12.2 *

Significance is shown as

^*p < 0.05 compared to non-morphine-treated controls,

^#p < 0.05 compared to morphine S.C. injection,

^$p < 0.05 compared to osmotic pump as determined by a two-way ANOVA with a Student-Newman-Keuls post hoc test.