Increased Expression of TRPV1 in the Cortex and Hippocampus from Patients with Mesial Temporal Lobe Epilepsy

  • PDF / 1,555,743 Bytes
  • 12 Pages / 595.276 x 790.866 pts Page_size
  • 56 Downloads / 231 Views

DOWNLOAD

REPORT


Increased Expression of TRPV1 in the Cortex and Hippocampus from Patients with Mesial Temporal Lobe Epilepsy Fei-Ji Sun & Wei Guo & Da-Hai Zheng & Chun-Qing Zhang & Song Li & Shi-Yong Liu & Qing Yin & Hui Yang & Hai-Feng Shu

Received: 15 July 2012 / Accepted: 14 August 2012 # Springer Science+Business Media, LLC 2012

Abstract Transient receptor potential vanilloid type-1 (TRPV1) is a ligand-gated nonselective cation channel that has been well characterized in peripheral pain pathway. Recent evidence from animal models of temporal lobe epilepsy (TLE) has supported the important role of TRPV1 in epileptogenesis. In this study, we investigated the expression and cellular distribution of TRPV1 in the temporal cortex (CTX) and hippocampus (HPC) from 26 patients with mesial TLE (MTLE) compared with 12 histologically normal samples. Reverse transcription-PCR and Western blotting revealed up-regulated mRNA and protein levels of TRPV1 in the MTLE group versus the control group. Immunohistochemistry data demonstrated that TRPV1 was mainly distributed in the cell bodies and dendrites of neurons. Double-labeled immunofluorescence further revealed that TRPV1 was localized on NeuN-positive neurons and GFAP-positive astrocytes, but not on HLA-positive microglia. In addition, its co-localization with glutamate and gamma-aminobutyric acid (GABA) indicated that TRPV1 was distributed on both glutamatergic and GABAergic neurons. Moreover, nerve growth factor, a sensitizing factor for TRPV1, was showed a higher expression pattern in MTLE patients. Taken together, our findings suggest that the overexpression and distribution patterns of TRPV1 might be Electronic supplementary material The online version of this article (doi:10.1007/s12031-012-9878-2) contains supplementary material, which is available to authorized users. F.-J. Sun : W. Guo : D.-H. Zheng : C.-Q. Zhang : S. Li : S.-Y. Liu : Q. Yin : H. Yang (*) : H.-F. Shu (*) Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, 2-V Xinqiao Street, Chongqing 400037, China e-mail: [email protected] e-mail: [email protected]

involved in the pathogenesis and epileptogenesis of human MTLE. Keywords Mesial temporal lobe epilepsy . Transient receptor potential vanilloid type-1 . Temporal cortex . Hippocampus

Introduction Mesial temporal lobe epilepsy (MTLE) represents the most common form of chronic and intractable epilepsy, with an imbalance between excitation and inhibition mostly confined to the hippocampus and the ipsilateral temporal lobe (Langlois et al. 2010). MTLE is characterized by spontaneous, progressive, and recurrent seizures and is often associated with hippocampal sclerosis (HS), including extensive neuron loss in the CA1 and CA3 regions and the hilus of the dentate gyrus, astroglial proliferation, mossy fiber sprouting, and strong synaptic reorganization (Bae et al. 2010). Most patients with MTLE become drug-resistant, and an anteromedial temporal lobectomy with hippocampectomy is needed for seizure control (Spencer et al. 1984; Chabard