30 Decreases in astrocytic immunoreactivity for cellular GFAP and the neuron-specific phosphoprotein B50 (or GAP-45) were detected in CA1 and CA2 in depression.31 The authors suggest that apoptosis may only be a minor contributor to volume changes in the hippocampus in depression, while patterns of reactive astrogliosis and synaptic
reorganization proteins are significantly Inhibitors,research,lifescience,medical altered in only some hippocampal regions in depression. Other reports of hippocampal changes in mood disorders identify a significant decrease in the density of nonpyramidal neurons in the CA2 region and a reduction in reelin-positive cell density in the hilus in subjects with BPD.32,33 Two other studies conducted on the postmortem hippocampal formation in a small sample of subjects with
BPD reveal a decrease in the density and size Inhibitors,research,lifescience,medical of nonpyramidal neurons in the CA2 region and some disorganization in neuronal clusters in layers II and III of the entorhinal cortex.34,35 Neuronal and glial cell packing density and soma size were estimated recently in Nissl-stained sections including the hippocampal subfields in 16 subjects with MDD and 16 age-matched normal control subjects.36 Representative photomicrographs are presented in Figure 2. Prominent abnormalities in the CA regions and dentate gyrus are found in subjects with MDD. There Inhibitors,research,lifescience,medical is a significant increase in the mean density of pyramidal neurons in depressed subjects, as compared with normal control subjects. In the granule cell layer of the dentate gyrus, cell density is significantly increased in MDD. In addition, there is a significant decrease in the mean soma size Inhibitors,research,lifescience,medical of pyramidal neurons in depressed subjects, as compared with normal control subjects. On the basis of covariate analyses, the main findings of increased neuronal density
and decreased neuron Inhibitors,research,lifescience,medical soma size in PH-797804 molecular weight depression are not significantly altered when taking into consideration such factors as gender, age, postmortem interval, tissue pH, brain weight, smoking, antidepressant, drug prescription in the last month of life, or suicide. The substantial increases noted in neuronal packing density and decrease in neuronal (-)-p-Bromotetramisole Oxalate soma size detected in postmortem tissue may be related to the decrease in hippocampal volume noted by some in MDD. Figure 2. Brightfield photomicrographs of coronal sections of the postmortem human hippocampal formation. A. Cresyl violet-stained coronal section from a 54-year-old male (23-h postmortem interval). B. An adjacent coronal section processed byTimm staining. Note … Glial pathology in depression appears to extend beyond the frontal cortex to the hippocampus. A recent study of the hippocampus in a large number of subjects with MDD and aged-matched normal control subjects reports a significant increase in the density of glial cells in all hippocampal CA subfields and the granule cell layer of the dentate gyrus.