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Methamphetamine (METH) administration alters gene expression in the nucleus accumbens (NAc). We recently demonstrated that an acute METH injection produced prolonged increases in the expression of immediate early genes in the NAc of HDAC2-deficient mice, suggesting that HDAC2 might be an important regulator of gene expression in the rodent brain. Here, we tested the possibility that HDAC2 deletion might also impact METH-induced changes in the expression of various HDAC classes in the NAc. Wild-type (WT) and HDAC2 knockout (KO) mice were given a METH (20 mg/kg) injection, and NAc tissue was collected at 1, 2, and 8 h post treatment. We found that METH decreased HDAC3, HDAC4, HDAC7, HDAC8, and HDAC11 mRNA expression but increased HDAC6 mRNA levels in the NAc of WT mice. In contrast, the METH injection increased HDAC3, HDAC4, HDAC7, HDAC8, and HDAC11 mRNA levels in HDAC2KO mice. These observations suggest that METH may induce large-scale transcriptional changes in the NAc by regulating the expression of several HDACs, in part, via HDAC2-dependent mechanisms since some of the HDACs showed differential responses between the two genotypes. Our findings further implicate HDACs as potential novel therapeutic targets for neurotoxic complications associated with the abuse of certain psychostimulants. [ABSTRACT FROM AUTHOR]

Multidrug resistance protein 1a (MDR1a) potentiated methylenedioxymethamphetamine (MDMA)-induced decreases of dopamine (DA) and dopamine transport protein in mouse brain one week after MDMA administration. In the present study, we examined if mdr1a wild-type (mdr1a +/+) and knock-out (mdr1a −/−) mice differentially handle the acute effects of MDMA on the nigrostriatal DA system 0–24 h following a single drug injection. 3-way ANOVA revealed significant 2-way interactions of strain × time ( F5,152 = 32.4, P < 0.001) and strain × dose ( F3,152 = 25.8, P < 0.001) on 3,4-dihydroxyphenylacetic acid (DOPAC)/DA ratios in mdr1a +/+ and −/− mice. 0.3–3 h after 10 mg/kg MDMA, DOPAC/DA ratios were increased in mdr1a +/+ mice, but decreased 0.3–1 h after MDMA in mdr1a −/− mice. Twenty-four hours after 10 mg/kg MDMA, DOPAC/DA ratios were increased 600% in mdr1a +/+ mice compared to saline-treated control mice, while in mdr1a −/− mice DOPAC/DA ratios were unchanged. Striatal MDMA and its metabolite, methylenedioxyamphetamine, concentrations by gas chromatography–mass spectrometry were similar in both strains 0.3–4 h after MDMA, discounting the role of MDR1a-facilitated MDMA transport in observed inter-strain differences. Increased DOPAC/DA turnover in mdr1a +/+ mice following MDMA is consistent with the previous report that MDMA neurotoxicity is increased in mdr1a +/+ mice. Increased DA turnover via monoamine oxidase in mdr1a +/+ vs −/− mice might increase exposure to neurotoxic reactive oxygen species. [ABSTRACT FROM AUTHOR]