1999), this is likely an adaptive response designed to protect against oxidative damage (Hilbert and Mohsenin 1996). Over the longer term, chronic cigarette exposure appears to overwhelm these adaptive

host antioxidant responses (Hulea et al. 1995; Anbarasi et al. 2006a) leaving the system vulnerable to cellular damage. The importance of deterioration in antioxidant levels is underlined by the fact that cigarette smoke-induced increases in markers of lipid peroxidation are prevented by vitamin E (Thome et al. 2011). Furthermore, another study demonstrated that active exercise Inhibitors,research,lifescience,medical reduced NVP-BEZ235 concentration expression of oxidative stress produced secondary to cigarette smoke exposure in rats (Tuon et al. 2010). The ability of exercise to modulate oxidative stress may also partially underpin its therapeutic effect on anxiety disorders (Moylan et al. 2013). Exogenous nicotine

administration to isolated cell lines in vitro reduces antioxidant constituents (e.g., glutathione) Inhibitors,research,lifescience,medical and increases markers of lipid peroxidation (MDA) and lactate dehydrogenase activity (Yildiz et al. 1998, 1999), effects blocked by addition of detoxifying enzymes SOD and CAT (Yildiz et al. 1998, 1999). Investigations into the effects of nicotine on oxidative stress in CNS cells have been more limited. In a study that utilized chronic Inhibitors,research,lifescience,medical nicotine exposure administered for 10 days, results demonstrated increased levels of TBARS and HNE (4-hydroxynonenal) in the brain (Bhagwat et al. 1998). Cigarette smoke can also increase levels of brain heat shock protein Inhibitors,research,lifescience,medical 70 kDa (Anbarasi et al.

2006b). Only one study to our knowledge has simultaneously assessed the association between cigarette smoke exposure, anxiety symptoms, and brain oxidative stress markers. In this study, rats exposed to cigarette smoke showed increased markers of brain lipid peroxidation and decreased plasma ascorbic acid. When rats were additionally treated with pecan nut shell extract, a substance with antioxidant properties, improvements were demonstrated in anxiety symptoms (interpreted as withdrawal symptoms) Inhibitors,research,lifescience,medical and markers of lipid peroxidation (Reckziegel et al. 2011). Mitochondrial function Mitochondria are important sources of oxidative stress and many abnormalities in mitochondrial function have been found in psychiatric disorders (for review see Manji et al. 2012). Although still requiring much investigation, multiple to factors support a role for mitochondrial dysfunction in increasing anxiety. First, patients exhibiting mitochondrial disorders commonly demonstrate psychiatric symptoms including increased anxiety (Miyaoka et al. 1997; Anglin et al. 2012). Second, recent investigations have discovered decreased levels of glycolysis enzymes coupled with increased expression of components associated with the electron transport chain in high-anxiety trait animal models, potentially increasing vulnerability to production of ROS and subsequent cellular damage (Filiou et al. 2011).