title: TRPV1 receptors augment basal synaptic transmission in CA1 and CA3 pyramidal neurons in epilepsy.
abstract: Temporal lobe epilepsy in human and animals is attributed to alterations in brain function especially hippocampus formation. Changes in synaptic activity might be causally related to the alterations during epileptogenesis. Transient receptor potential vanilloid 1 (TRPV1) as one of the non-selective ion channels has been shown to be involved in synaptic transmission. However, the potential role of TRPV1 receptors in synaptic function in the epileptic brain needs to be elucidated. In the present study, we used quantitative real-time PCR (qRT-PCR), western blotting, and immunohistochemistry to assess hippocampal TRPV1 mRNA expression, protein content, and distribution. Moreover, the effects of pharmacologic activation and inhibition of TRPV1 receptors on the slope of evoked field excitatory postsynaptic potentials (fEPSPs) were analyzed in CA1 and CA3 pyramidal neurons, after 3months of pilocarpine-induced status epilepticus (SE). SE induced an upregulation of TRPV1 mRNA and protein content in the whole hippocampal extract, as well as its distribution in both CA1 and CA3 regions. Activation and inhibition of TRPV1 receptors (via capsaicin 1μM and capsazepine 10μM, respectively) did not influence basal synaptic transmission in CA1 and CA3 regions of control slices, however, capsaicin increased and capsazepine decreased synaptic transmission in both regions in tissues from epileptic animals. Taken together, these findings suggest that a higher expression of TRPV1 in the epileptic condition is accompanied by alterations in basal synaptic transmission.
authors.affiliation: Department of Neuroscience, School of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran; Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran; Shefa Neuroscience Research Center, Khatam-Al-Anbia Hospital, Tehran, Iran.
authors.forename: F
authors.initials: F
authors.lastname: Saffarzadeh
authors.affiliation: Department of Neuroscience, School of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran; Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran; Shefa Neuroscience Research Center, Khatam-Al-Anbia Hospital, Tehran, Iran.
authors.forename: M J
authors.initials: MJ
authors.lastname: Eslamizade
authors.affiliation: Shefa Neuroscience Research Center, Khatam-Al-Anbia Hospital, Tehran, Iran.
authors.forename: S M M
authors.initials: SM
authors.lastname: Mousavi
authors.affiliation: Shefa Neuroscience Research Center, Khatam-Al-Anbia Hospital, Tehran, Iran.
authors.forename: S B
authors.initials: SB
authors.lastname: Abraki
authors.affiliation: Brain and Spinal Cord Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Neuroscience, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: M R
authors.initials: MR
authors.lastname: Hadjighassem
authors.affiliation: Shefa Neuroscience Research Center, Khatam-Al-Anbia Hospital, Tehran, Iran; Institut für Physiologie I, Klinik und Poliklinik fur Neurochirurgie, Department of Neurology, Epilepsy Research Center, Westfälische Wilhelms-Universität Münster, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Gorji
mesh_terms: D000818:Animals; D002211:Capsaicin / Q000008:administration & dosage / Q000031:analogs & derivatives; D004195:Disease Models, Animal; D004833:Epilepsy, Temporal Lobe / Q000139:chemically induced / Q000378:metabolism*; D019706:Excitatory Postsynaptic Potentials; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D010862:Pilocarpine; D017966:Pyramidal Cells / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D017208:Rats, Wistar; D050916:TRPV Cation Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D050916:TRPV Cation Channels; C476722:Trpv2 protein, rat; D010862:Pilocarpine; C071423:capsazepine; D002211:Capsaicin
keywords: CA1; CA3; TRPV1; hippocampus; synaptic transmission; temporal lobe epilepsy