Control rats (n = 6; implanted but not Compound Library price stimulated) and rats that did not develop SE during stimulation (non-SE rats; killed 3–4 months after stimulation (n = 4), were also included. Rats were disconnected from the EEG recording set-up and deeply anaesthetized with pentobarbital (Nembutal, intraperitoneally, 60 mg/kg). For immunocytochemistry, the animals were perfused through the ascending aorta with 300 mL of 0.37% Na2S solution, followed by 300 mL 4% paraformaldehyde in 0.1 m phosphate buffer, pH 7.4. Thereafter, the brains were removed, incubated for 72 h in 0.3 m EDTA, pH 6.7 (Merck,

Amsterdam, The Netherlands) and paraffin embedded. Paraffin-embedded tissue was sectioned at 6 μm, mounted on pre-coated glass slides (Star Frost, Waldemar Knittel GmbH, Brunschweig, Germany) and used for in situ hybridizations and immunocytochemistry. Horizontal sections were analysed at a mid-level of the brain (5300–6100 μm below cortex surface). In situ hybridization

was performed on two adjacent serial hippocampal sections from each group (control, n = 6; 24 h, n = 4; 1 week, n = 6; 3–4 months, n = 6). Two additional serial slices were used for the double-staining, combining in situ hybridization with immunocytochemistry (in the same slices) with different antibodies, as described below. The human cases included in this study were obtained from the files of the Department of Neuropathology of the Academic Medical Center (AMC, University of Amsterdam) and the VU University Medical Center (VUMC). Ten patients LEE011 ic50 Decitabine purchase underwent resection of the hippocampus for medically intractable TLE. Informed consent was obtained for the use of brain tissue and for access to medical records for research

purposes. All samples were obtained and used in a manner compliant with the Declaration of Helsinki. Two neuropathologists reviewed all cases independently. In six cases a pathological diagnosis of HS (without extra-hippocampal pathology) was made. The HS specimens include four cases of classical HS (grade 3, mesial temporal sclerosis type 1a) and two cases of severe HS (grade IV; mesial temporal sclerosis type 1b; Wyler et al., 1992; Blumcke et al., 2007). Four non-HS cases, in which a focal lesion (ganglioglioma not involving the hippocampus proper) was identified, were also included to provide a comparison group to HS cases. Control hippocampal tissue was obtained at autopsy from five patients without history of seizures or other neurological diseases. Brain tissue from a patient with viral encephalitis was also used for in situ hybridization (as positive control for miR-146a expression). All autopsies were performed within 12 h after death. Table 1 summarizes the clinical features of TLE and control cases.