Cytomegalic Interneurons
Open Access
- 1 June 2007
- journal article
- research article
- Published by Oxford University Press (OUP) in Journal of Neuropathology and Experimental Neurology
- Vol. 66 (6), 491-504
- https://doi.org/10.1097/01.jnen.0000240473.50661.d8
Abstract
A defining histopathologic feature of Taylor-type cortical dysplasia (CD) is the presence of cytomegalic neurons and balloon cells. Most cytomegalic neurons appear to be pyramidal-shaped and glutamatergic. The present study demonstrates the presence of cytomegalic GABAergic interneurons in a subset of pediatric patients with severe CD. Cortical tissue samples from children with mild, severe, and non-CD pathologies were examined using morphologic and electrophysiologic techniques. By using in vitro slices, cytomegalic cells with characteristics consistent with interneurons were found in 6 of 10 patients with severe CD. Biocytin labeling demonstrated that cytomegalic interneurons had more dendrites than normal-appearing interneurons. Whole-cell patch clamp recordings showed that cytomegalic interneurons had increased membrane capacitance and time constant compared with normal-appearing interneurons. They also displayed signs of cellular hyperexcitability, evidenced by increased firing rates, decreased action potential inactivation, and the occurrence of spontaneous membrane depolarizations. Single-cell reverse transcription-polymerase chain reaction and immunohistochemistry for GABAergic markers provided further evidence that these cells were probably cytomegalic interneurons. The pathophysiologic significance of GABAergic cytomegalic interneurons in severe CD tissue is unknown, but they could inhibit glutamatergic cytomegalic pyramidal neurons, or contribute to the synchronization of neuronal networks and the propagation of ictal activity in a subset of pediatric patients with severe CD.Keywords
This publication has 49 references indexed in Scilit:
- Activation of mammalian target of rapamycin in cytomegalic neurons of human cortical dysplasiaAnnals of Neurology, 2006
- Dysfunction of Synaptic Inhibition in Epilepsy Associated with Focal Cortical DysplasiaJournal of Neuroscience, 2005
- Are Cytomegalic Neurons and Balloon Cells Generators of Epileptic Activity in Pediatric Cortical Dysplasia?Epilepsia, 2005
- Frequent coexpression of the vesicular glutamate transporter 1 and 2 genes, as well as coexpression with genes for choline acetyltransferase or glutamic acid decarboxylase in neurons of rat brainJournal of Neuroscience Research, 2005
- Microanatomy of the dysplastic neocortex from epileptic patientsBrain, 2004
- Expression of the vesicular glutamate transporters during development indicates the widespread corelease of multiple neurotransmittersJournal of Comparative Neurology, 2004
- Insulin signaling pathways in cortical dysplasia and TSC‐tubers: Tissue microarray analysisAnnals of Neurology, 2004
- Persistent sodium current in subicular neurons isolated from patients with temporal lobe epilepsyEuropean Journal of Neuroscience, 2004
- NMDA Receptor Alterations in Neurons from Pediatric Cortical Dysplasia TissueCerebral Cortex, 2004
- Is there more to gaba than synaptic inhibition?Nature Reviews Neuroscience, 2002