, 2008). Elevated plasma

NPY was detected in a study of individuals with panic disorder, in which the authors suggest that an increase in NPY may be compensatory to buffer enhanced sympathetic activation in this Vandetanib mw disorder (Boulenger et al., 1996). Other studies have not detected differences in NPY levels between healthy controls and persons with obsessive compulsive, social anxiety, or panic disorders (Stein and et al, 1996 and Altemus and et al, 1999), or have failed to identify genetic associations between NPY and anxiety disorders (Lindberg et al., 2006). Clinical investigations have revealed that the plasma and CSF of depressed individuals contain decreased concentrations of NPY compared to healthy controls (Hashimoto and et al, 1996, Heilig and et al, 2004, Hou and et al, 2006, Nilsson and et al, 1996 and Widerlov and et al, 1988). Additional studies have shown lower NPY in clinically depressed patients with a history of suicide attempts compared to healthy persons, and that NPY levels are lowest in individuals with a recent suicide attempt (Westrin et al., 1999). Likewise, low NPY immunoreactivity has been found in postmortem brain tissue of suicide victims, with the most robust reductions in NPY occurring in the brains of persons with a history of depression (Widdowson et al., 1992).

Low levels of NPY mRNA expression are also found in persons with bipolar disorder (Caberlotto MLN0128 clinical trial and Hurd, Mephenoxalone 1999 and Kuromitsu and et al, 2001). Genetic variants of the preproNPY gene have been associated with resilience or vulnerability to depression (Heilig and et al, 2004, Wang and et al, 2013 and Sjoholm and et al, 2009). For instance, a genetic polymorphism resulting in higher levels of mature NPY appears to be protective against depression despite exposure to environmental risk factors (Sjoholm et al., 2009), and the presence of this polymorphism is less frequent in depressed patients (Heilig et al., 2004). In another study, a genotype associated with low NPY expression was found to be overrepresented

in persons with major depression compared to healthy controls (Mickey et al., 2011). Interestingly, antidepressant strategies are associated with parallel elevations in NPY and decreases in corticotropin-releasing hormone (CRH), thereby supporting peptidergic interactions in the mechanisms underlying clinically efficacious treatments for depression. For example, CSF levels of NPY are elevated in depressed patients following electroconvulsive therapy, while levels of corticotropin-releasing hormone decrease concurrently (Mathé and et al, 1995 and Nikisch and Mathe, 2008). Increased NPY after treatment with the selective serotonin reuptake inhibitor citalopram is associated with a reduction in depression severity and the levels of CRH (Nikisch et al., 2005).