PT - JOURNAL ARTICLE AU - Elena Escubedo AU - Carlos Chipana AU - Mónica Pérez-Sánchez AU - Jordi Camarasa AU - David Pubill TI - Methyllycaconitine Prevents Methamphetamine-Induced Effects in Mouse Striatum: Involvement of α7 Nicotinic Receptors AID - 10.1124/jpet.105.089748 DP - 2005 Nov 01 TA - Journal of Pharmacology and Experimental Therapeutics PG - 658--667 VI - 315 IP - 2 4099 - http://jpet.aspetjournals.org/content/315/2/658.short 4100 - http://jpet.aspetjournals.org/content/315/2/658.full SO - J Pharmacol Exp Ther2005 Nov 01; 315 AB - In a previous study, we demonstrated that in rat striatal synaptosomes, methamphetamine (METH)-induced reactive oxygen species (ROS) production was prevented by methyllycaconitine (MLA), a specific antagonist of α7 neuronal nicotinic acetylcholine receptors (α7 nAChR). The aim of this study was to test the influence of MLA on acute METH effects and neurotoxicity in mice, using both in vivo and in vitro models. MLA inhibited METH-induced climbing behavior by 50%. Acute effects after 30-min preincubation with 1 μM METH also included a decrease in striatal synaptosome dopamine (DA) uptake, which was prevented by MLA. METH-induced neurotoxicity was assessed in vivo in terms of loss of striatal dopaminergic terminals (73%) and of tyrosine hydroxylase levels (by 90%) at 72 h post-treatment, which was significantly attenuated by MLA. Microglial activation [measured as 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxamide binding] was also present at 24 h post-treatment and was fully prevented by MLA, tending to confirm its neuroprotective activity. MLA had no effect on METH-induced hyperthermia. Additionally, flow cytometry assays showed that METH-induced ROS generation occurs inside synaptosomes from mouse striatum. This effect implied release of vesicular DA and was calcium-, neuronal nitric-oxide synthase-, and protein kinase C-dependent. MLA and α-bungarotoxin, but not dihydro-β-erythroidine (an antagonist that blocks nAChR-containing β2 subunits), fully prevented METH-induced ROS production without affecting vesicular DA uptake. The importance of this study lies not only in the neuroprotective effect elicited by the blockade of the α7 nicotinic receptors by MLA but also in that it proposes a new mechanism with which to study METH-induced acute and long-term effects. The American Society for Pharmacology and Experimental Therapeutics