“…The excessively high levels of extracellular dopamine induced by METH initiate a neurotoxic cascade producing free radicals and quinones that are damaging to proteins (Fornstedt and Carlsson, 1989; Hastings et al, 1996). The protracted overflow of dopamine induced by METH promotes the overflow of the excitotoxic transmitter glutamate (Nash and Yamamoto, 1992), nitric oxide production (Taraska and Finnegan, 1997; Zhu et al, 2009), microglial activation (LaVoie et al, 2004; Thomas et al, 2004), and bioenergetic compromise due to mitochondrial dysfunction (Chan et al, 1994; Brown and Yamamoto, 2003). The neurotoxic state induced by METH causes pre-synaptic neural damage including reduction of dopamine transporter function (Fleckenstein et al, 1997), oligomerization of the transporter (Baucum et al, 2004), decreased vesicular transporter function (Fleckenstein et al, 2003), inhibition of tyrosine hydroxylase activity (Hotchkiss et al, 1979), and protein levels (Yu et al, 2004), decreased tissue dopamine content (Wagner et al, 1980) and degeneration of striatal dopamine terminals (Ricaurte et al, 1982).…”