The growing body of evidence implicating tumor necrosis factor-α (TNFα) in the pathophysiology of psychiatric disorders led us to measure levels of that protein in the cortex of subjects with major depressive disorders (MDD). Having reported an increase (458%) in the levels of the transmembrane (tmTNFα), but not the soluble (sTNFα), form of the protein in Brodmann's area (BA) 46, but not 24, in people with the disorder, we decided to examine additional components of TNFα-related pathways in the same regions in people with MDD and extend our studies to the same cortical regions of people with schizophrenia (Sz) and bipolar disorders (BD). Using postmortem tissue, western blots and quantitative PCR, we have now shown there is a significant increase (305%) in tmTNFα in Brodmann's area 24, but not 46, from subjects with BD, and that levels of the protein were not altered in Sz. Levels of sTNFα were not altered in BD or Sz. In addition, we have shown that levels of TNF receptor 1 (TNFR1) mRNA are increased in BA 24 (53%) and BA 46 (82%) in people with Sz, whereas levels of TNFR2 mRNA was decreased in BA 46 in people with mood disorders (MDD=-51%; BD=-67%). Levels of proteins frequently used as surrogate markers of neuronal, astrocytic and microglia numbers, as well as levels of the pro-inflammatory marker (interleukin 1β), were not changed in the cortex of people with mood disorders. Our data suggest there are differential changes in TNFα-related markers in the cortex of people with MDD, BD and Sz that may not be related to classical inflammation and may cause changes in different TNFα-related signaling pathways.

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We have attempted to replicate studies showing higher levels of serotonin 2A receptors (HTR2A) in the cortex of people with mood disorders and to determine the effects of treating rats with antidepressant drugs on levels of that receptor. In situ [3H]ketanserin binding and autoradiography was used to measure levels of HTR2A in Brodmann's area (BA) 46 and 24 from people with major depressive disorders (MDD, n = 16), bipolar disorders (BD, n = 14) and healthy controls (n = 14) as well as the central nervous system (CNS) of rats (20 per treatment arm) treated for 10 or 28 d with fluoxetine (10 mg/kg/d) or imipramine (20 mg/kg/d). Compared with controls, HTR2A were lower in BA 24, but not BA 46, from people with MDD (p = 0.005); HTR2A were not changed in BD. Levels of HTR2A were lower in BA 24 (p = 0.007), but not BA 46, from people who had died by suicide. Finally, levels of HTR2A were lower in the CNS of rats treated with imipramine, but not fluoxetine, for 28 d, but not 10 d. From our current and previous data we conclude cortical HTR2A are lower in schizophrenia, MDD, people with mood disorders who died by suicide, rats treated with some antipsychotic or some antidepressant drugs. As levels of cortical HTR2A can be affected by the aetiologies of different disorders and mechanisms of action of different drugs, a better understanding of how such changes can occur needs to be elucidated.