Polyamines and polyamine-metabolizing enzymes in schizophrenia: Current knowledge and concepts of therapy

Figure 1 Cellular localization of polyamine-metabolizing enzymes and antizyme inhibitor 2 in human and rat brain with nickel-enhanced streptavidin-biotin immunocytochemistry. A: Ornithine decarboxylase immunoreactive neurons of the human prefrontal cortex. Bar = 70 µm; B: Antizyme inhibitor 2 expressing neurons in the human prefrontal cortex. Bar = 30 µm; C: Antizyme inhibitor 2 immunoreactive fiber in the human temporal cortex. Note the typical pearlchain-like structure as already described by others[18]. Bar = 20 µm; D: Strong spermine oxidase immunoreactive neurons in the human hypothalamus (interstitial nucleus). Bar = 30 µm; E: Multiple spermine oxidase expressing neurons in the CA2 region of the human hippocampus. Bar = 30 µm; F: Spermine oxidase expressing neurons in rat medial prefrontal cortex. Bar = 55 µm; G: Low power microphotograph of agmatinase immunoreactivity in human habenula. Bar = 140 µm; H: Single agmatinase immunopositive neuron in the human insular cortex. Bar = 30 µm.

Figure 2 Major pathways of polyamines biosynthesis and interconversion (from Gross and Turecki[71]; scheme reproduced with permission of Bentham; modified). ADC: Arginine decarboxylase; AGMAT: Agmatinase; AMD: S-adenosylmethionine decarboxylase; ARG: Arginase; AZIN: Ornithine decarboxylase antizyme inhibitor; dcSAM: Decarboxylated S-adenosylmethionine; MTA: 5’-methylthioadenosine; OAT: Ornithine aminotransferase; OAZ: Ornithine decarboxylase antizyme; ODC: Ornithine decarboxylase; PAO: Polyamine oxidase; SAM: S-adenosylmethionine; SAT1: Spermidine/SpermineN1 acetyltransferase; SMS: Spermine synthase; SMOX: Spermine oxidase; SRM: Spermidine synthase.