Table 2.

Chronic morphine pretreatment in vivo increases TNFα release ex vivo in dorsal spinal cord

	Saline in vivo	Morphine in vivo
Media	47.89±15.05	71.78±8.73
LPS	77.70±13.26	130.84±16.15

Spinal cord sections were isolated from rats that were dosed with morphine or vehicle at 5mg/kg b.i.d. for 5 days (n = 6/group), 2 days after the conclusion of dosing. Tissue was incubated with LPS or media control for 3 h, and the supernatants collected for TNFα protein (mean ±SEM, pg/ml). There was a main effect of morphine (P<0.01) and a main effect of LPS (P<0.01). There were no significant interactions between morphine and LPS. Detection limits were 6.25–1600 pg/ml.