Diclofenac increases P-gp-mediated transport of morphine at the BBB.

<p>The effect of λ-carrageenan treatment on brain uptake [³H]morphine (36.7 µg/rat) was determined by <i>in situ</i> brain perfusion. Animals received subcutaneous injections of saline or λ-carrageenan into the plantar surface of the right hind paw. 15 min after paw treatment animals received saline (1 mL/kg, i.p.) or diclofenac (30 mg/kg, i.p.). 3 h post paw treatment animals were perfused with [³H]morphine (0.5 mCi/mL) for 10 min. Morphine brain accumulation was significantly decreased in animals that received saline paw injections with diclofenac i.p. injections (Sal/Diclo) and in animals that received λ-carrageenan paw injections with saline i.p. injections (Carr/Sal) as compared to saline treated (Sal/Sal) animals. Results are expressed as mean ± SEM of at least 6 individual animals per treatment group. Asterisks represent data points that are significantly different (*p<0.05).