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. 2016 Aug 16;6(8):e871. doi: 10.1038/tp.2016.144

Figure 4.

Figure 4

Dendrograms showing the similarities in the degree of expression of l-arginine (arginine) and its three main metabolites l-citrulline (citrulline), l-ornithine (ornithine) and agmatine in the frontal cortex (BA8) from non-psychiatric control (a) and schizophrenia (b) cases (n=20 per group). The numbers indicate the distance levels (arbitrary unit) between arginine and each metabolite. (c) Arginine metabolic pathways. l-arginine can be metabolised by NOS, arginase and ADC to form a number of bioactive molecules (see the Introduction for detailed description). We found increased levels of arginase activity, arginase II protein expression and agmatine tissue concentration (indicated by the red letters and arrows), and reduced eNOS protein expression and GABA level (indicated by the green letters and arrows) in the schizophrenia cases. ADC, arginine decarboxylase; BA8, Brodmann's area 8; eNOS, endothelial NOS; GABA, γ-aminobutyric acid; iNOS, inducible NOS; NO, nitric oxide; NOS, nitric oxide synthase; nNOS, neuronal NOS.