Fig. 8.

Amino acid levels (pmol/mg) are significantly altered by Tat exposure or morphine depending on the CNS region assessed. The concentrations of various amino acids were assessed in the striatum and spinal cord on saline and morphine-treated Tat transgenic mice using hydrophilic interaction chromatography (HILIC)-LC/MS/MS. Amino acid concentrations were normalized to pmol/mg of tissue. a In the striatum, morphine significantly upregulated phenylalanine and proline concentrations, and significantly downregulated serine levels in Tat(+) and Tat(−) mice. b In the spinal cord, Tat expression increased leucine and valine levels, whereas morphine significantly decreased valine and tyrosine levels. All data are expressed as mean ± SEM. Statistical significance was assessed by ANOVA followed by Tukey’s post hoc test; *p < 0.05 main effect of drug; ^#p < 0.05 main effect of genotype; ^§p < 0.05 vs. saline-exposed Tat(+) mice. Morph short-term (8-day) morphine injections. n = 3–5 mice per group