Some notes on insulin-regulated aminopeptidase in depression

Abstract

We read with great interest the recently published article by Loyens et al. (2012) about the putative role of insulin-regulated aminopeptidase (IRAP) in mediating the antidepressant-like effects of oxytocin (OT) and wish to comment from a ‘human’ perspective on selected aspects of this topic. Loyens and colleagues have demonstrated that the antidepressant-like effect of subcutaneously administered OT in the forced swim test is absent in IRAP knockout mice and abolished by angiotensin IV in IRAP wild-type mice (Loyens et al., 2012). Since OT is increasingly discussed as a promising therapeutic target for depression (reviewed in Slattery and Neumann 2010), we would like to add some thoughts concerning the emerging role of IRAP in human mood disorders. As part of our ongoing search for implications of IRAP for neuropsychiatric disorders (Bernstein et al., 2011), we have performed immunohistochemical studies on the expression of IRAP in human post mortem brains of individuals with affective disorders. In particular, we were interested in elucidating possible alterations of IRAP expression …