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Fig. 1 | BMC Neuroscience

Fig. 1

From: Chronic oxycodone induces integrated stress response in rat brain

Fig. 1

Model for chronic exposure to oxycodone dosing. a Hot plate assay to test the antinociceptive effect of oxycodone and the time of tolerance development in rats. Oxycodone (7.5 or 15 mg/kg) or water was administered by oral gavage every 24 h for 29 days. Rats were placed on a hot plate and the time spent until they licked the hind paw was measured. Each point represents a mean value of measurement from 8 animals (±SEM). There was an effect of treatment (F2, 21 = 26.08, p < 0.0001), day (F7, 147 = 14.03, p < 0.0001) and a treatment × day interaction (F14, 147 = 5.38, p < 0.0001). *p < 0.05 vs water; # p < 0.05 vs oxy 7.5 mg/kg (Fisher’s PLSD). Oxy oxycodone; water vehicle treatment. b Western blot analyses of signalling pathways of rewarding circuit in nucleus accumbens. Representative images of western blots of total and phosphorylated CaMKII, total and phosphorylated PKA, total and phosphorylated Erk1/2, cFos, and GAPDH in nucleus accumbens of water (W) and oxycodone (O) treated rats. Below panel—graphs representing the densitometric analysis of western blots. The graphs represent the mean ratio of phosphorylated protein to corresponding total protein, and mean ratio of cFos to GAPDH. Oxycodone data were normalized to that in water samples from three different drug administration experiments (±SEM). Data was analyzed by Student’s t test. P-CaMKII/CaMKII, p < 0.001; P-PKA/PKA, p < 0.05; P-Erk1/2/Erk1/2, p < 0.05; cFos/GAPGH, p < 0.05. Open bars water samples; gray filled bars oxycodone samples

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