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Dusing MR, LaSarge CL, Drake AW, Westerkamp GC, McCoy C, Hetzer SM, Kraus KL, Pedapati EV, Danzer SC. Transient Seizure Clusters and Epileptiform Activity Following Widespread Bilateral Hippocampal Interneuron Ablation. eNeuro 2024; 11:ENEURO.0317-23.2024. [PMID: 38575351 PMCID: PMC11036118 DOI: 10.1523/eneuro.0317-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 03/28/2024] [Accepted: 03/29/2024] [Indexed: 04/06/2024] Open
Abstract
Interneuron loss is a prominent feature of temporal lobe epilepsy in both animals and humans and is hypothesized to be critical for epileptogenesis. As loss occurs concurrently with numerous other potentially proepileptogenic changes, however, the impact of interneuron loss in isolation remains unclear. For the present study, we developed an intersectional genetic approach to induce bilateral diphtheria toxin-mediated deletion of Vgat-expressing interneurons from dorsal and ventral hippocampus. In a separate group of mice, the same population was targeted for transient neuronal silencing with DREADDs. Interneuron ablation produced dramatic seizure clusters and persistent epileptiform activity. Surprisingly, after 1 week seizure activity declined precipitously and persistent epileptiform activity disappeared. Occasional seizures (≈1/day) persisted to the end of the experiment at 4 weeks. In contrast to the dramatic impact of interneuron ablation, transient silencing produced large numbers of interictal spikes, a significant but modest increase in seizure occurrence and changes in EEG frequency band power. Taken together, findings suggest that the hippocampus regains relative homeostasis-with occasional breakthrough seizures-in the face of an extensive and abrupt loss of interneurons.
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Affiliation(s)
- Mary R Dusing
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039
| | - Candi L LaSarge
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, Ohio 45229-3039
| | - Austin W Drake
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, Ohio 45229-3039
- Medical Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, Ohio 45229-3039
| | - Grace C Westerkamp
- Division of Child Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039
| | - Carlie McCoy
- Division of Neurosurgery, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039
| | - Shelby M Hetzer
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, Ohio 45229-3039
| | - Kimberly L Kraus
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, Ohio 45229-3039
- Medical Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, Ohio 45229-3039
| | - Ernest V Pedapati
- Division of Child Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039
| | - Steve C Danzer
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, Ohio 45229-3039
- Medical Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, Ohio 45229-3039
- Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45229-3039
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Saporin as a Commercial Reagent: Its Uses and Unexpected Impacts in the Biological Sciences—Tools from the Plant Kingdom. Toxins (Basel) 2022; 14:toxins14030184. [PMID: 35324681 PMCID: PMC8952126 DOI: 10.3390/toxins14030184] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/23/2022] [Accepted: 02/23/2022] [Indexed: 02/02/2023] Open
Abstract
Saporin is a ribosome-inactivating protein that can cause inhibition of protein synthesis and causes cell death when delivered inside a cell. Development of commercial Saporin results in a technology termed ‘molecular surgery’, with Saporin as the scalpel. Its low toxicity (it has no efficient method of cell entry) and sturdy structure make Saporin a safe and simple molecule for many purposes. The most popular applications use experimental molecules that deliver Saporin via an add-on targeting molecule. These add-ons come in several forms: peptides, protein ligands, antibodies, even DNA fragments that mimic cell-binding ligands. Cells that do not express the targeted cell surface marker will not be affected. This review will highlight some newer efforts and discuss significant and unexpected impacts on science that molecular surgery has yielded over the last almost four decades. There are remarkable changes in fields such as the Neurosciences with models for Alzheimer’s Disease and epilepsy, and game-changing effects in the study of pain and itch. Many other uses are also discussed to record the wide-reaching impact of Saporin in research and drug development.
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de Curtis M, Rossetti AO, Verde DV, van Vliet EA, Ekdahl CT. Brain pathology in focal status epilepticus: evidence from experimental models. Neurosci Biobehav Rev 2021; 131:834-846. [PMID: 34517036 DOI: 10.1016/j.neubiorev.2021.09.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 09/02/2021] [Accepted: 09/05/2021] [Indexed: 12/01/2022]
Abstract
Status Epilepticus (SE) is often a neurological emergency characterized by abnormally sustained, longer than habitual seizures. The new ILAE classification reports that SE "…can have long-term consequences including neuronal death, neuronal injury…depending on the type and duration of seizures". While it is accepted that generalized convulsive SE exerts detrimental effects on the brain, it is not clear if other forms of SE, such as focal non-convulsive SE, leads to brain pathology and contributes to long-term deficits in patients. With the available clinical and experimental data, it is hard to discriminate the specific action of the underlying SE etiologies from that exerted by epileptiform activity. This information is highly relevant in the clinic for better treatment stratification, which may include both medical and surgical intervention for seizure control. Here we review experimental studies of focal SE, with an emphasis on focal non-convulsive SE. We present a repertoire of brain pathologies observed in the most commonly used animal models and attempt to establish a link between experimental findings and human condition(s). The extensive literature on focal SE animal models suggest that the current approaches have significant limitations in terms of translatability of the findings to the clinic. We highlight the need for a more stringent description of SE features and brain pathology in experimental studies in animal models, to improve the accuracy in predicting clinical translation.
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Affiliation(s)
- Marco de Curtis
- Epilepsy Unit, Fondazione IRCCS Istituto NeurologicoCarlo Besta, Milano, Italy.
| | - Andrea O Rossetti
- Department of Clinical Neuroscience, University Hospital (CHUV) and University of Lausanne, Lausanne, Switzerland
| | - Diogo Vila Verde
- Epilepsy Unit, Fondazione IRCCS Istituto NeurologicoCarlo Besta, Milano, Italy
| | - Erwin A van Vliet
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Science Park 904, P.O. Box 94246, 1090 GE, Amsterdam, the Netherlands; Amsterdam UMC, University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands
| | - Christine T Ekdahl
- Division of Clinical Neurophysiology, Lund University, Sweden; Lund Epilepsy Center, Dept Clinical Sciences, Lund University, Sweden
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Possible contribution of cerebellar disinhibition in epilepsy. Epilepsy Behav 2021; 118:107944. [PMID: 33887658 DOI: 10.1016/j.yebeh.2021.107944] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 02/07/2023]
Abstract
OBJECTIVE We hypothesize that loss of inhibition from the cerebellum can lead to cortical activation and seizures. BACKGROUND The traditional model for development of seizures purports that the source of seizures is increased electrical activity originating from cerebral cortical neurons. Studies have shown a decrease in inhibition results in a shift of cortical activity to a hyperexcitable state, which may lead to seizures. Interestingly, a 1978 study suggested the term "disorder of disinhibition" as a way to describe epilepsy from studies of chronic cerebellar stimulation. DESIGN/METHODS Cases and experimental studies in which cerebellar lesions have been implicated in the development of seizures were reviewed. Cases in which cerebellar inhibition has been targeted in the treatment of seizures were also included. Twenty-six studies and case reports are presented for this report. RESULTS The cases show cerebellar lesions can lead to cortical epileptiform activity. Purkinje cell loss is linked to the occurrence of seizures in animals. The majority of patients with cerebellar lesions were seizure free after complete resection, while less than half of patients were seizure free after partial resection. Novel treatments using deep-brain stimulation targeting cerebellar structures demonstrated therapeutic benefits for seizures. CONCLUSIONS Although pathophysiology is not well-understood, the cerebellum likely plays an inherent role in inhibiting aberrant cortical epileptogenesis. Cerebellar lesions may cause seizures due to loss of the inhibition of cortical areas or through intrinsic epileptic activity. Treatments enhancing cerebellar stimulation have shown therapeutic benefits in treating seizures, which could potentially provide another avenue for treatment.
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Lu J, West MB, Du X, Cai Q, Ewert DL, Cheng W, Nakmali D, Li W, Huang X, Kopke RD. Electrophysiological assessment and pharmacological treatment of blast-induced tinnitus. PLoS One 2021; 16:e0243903. [PMID: 33411811 PMCID: PMC7790300 DOI: 10.1371/journal.pone.0243903] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 12/01/2020] [Indexed: 11/19/2022] Open
Abstract
Tinnitus, the phantom perception of sound, often occurs as a clinical sequela of auditory traumas. In an effort to develop an objective test and therapeutic approach for tinnitus, the present study was performed in blast-exposed rats and focused on measurements of auditory brainstem responses (ABRs), prepulse inhibition of the acoustic startle response, and presynaptic ribbon densities on cochlear inner hair cells (IHCs). Although the exact mechanism is unknown, the “central gain theory” posits that tinnitus is a perceptual indicator of abnormal increases in the gain (or neural amplification) of the central auditory system to compensate for peripheral loss of sensory input from the cochlea. Our data from vehicle-treated rats supports this rationale; namely, blast-induced cochlear synaptopathy correlated with imbalanced elevations in the ratio of centrally-derived ABR wave V amplitudes to peripherally-derived wave I amplitudes, resulting in behavioral evidence of tinnitus. Logistic regression modeling demonstrated that the ABR wave V/I amplitude ratio served as a reliable metric for objectively identifying tinnitus. Furthermore, histopathological examinations in blast-exposed rats revealed tinnitus-related changes in the expression patterns of key plasticity factors in the central auditory pathway, including chronic loss of Arc/Arg3.1 mobilization. Using a formulation of N-acetylcysteine (NAC) and disodium 2,4-disulfophenyl-N-tert-butylnitrone (HPN-07) as a therapeutic for addressing blast-induced neurodegeneration, we measured a significant treatment effect on preservation or restoration of IHC ribbon synapses, normalization of ABR wave V/I amplitude ratios, and reduced behavioral evidence of tinnitus in blast-exposed rats, all of which accorded with mitigated histopathological evidence of tinnitus-related neuropathy and maladaptive neuroplasticity.
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Affiliation(s)
- Jianzhong Lu
- Hough Ear Institute, Oklahoma City, Oklahoma, United States of America
| | - Matthew B. West
- Hough Ear Institute, Oklahoma City, Oklahoma, United States of America
| | - Xiaoping Du
- Hough Ear Institute, Oklahoma City, Oklahoma, United States of America
| | - Qunfeng Cai
- Hough Ear Institute, Oklahoma City, Oklahoma, United States of America
| | - Donald L. Ewert
- Hough Ear Institute, Oklahoma City, Oklahoma, United States of America
| | - Weihua Cheng
- Hough Ear Institute, Oklahoma City, Oklahoma, United States of America
| | - Don Nakmali
- Hough Ear Institute, Oklahoma City, Oklahoma, United States of America
| | - Wei Li
- Hough Ear Institute, Oklahoma City, Oklahoma, United States of America
| | - Xiangping Huang
- Hough Ear Institute, Oklahoma City, Oklahoma, United States of America
| | - Richard D. Kopke
- Hough Ear Institute, Oklahoma City, Oklahoma, United States of America
- Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
- Departments of Physiology and Otolaryngology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- * E-mail:
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Putra M, Puttachary S, Liu G, Lee G, Thippeswamy T. Fyn-tau Ablation Modifies PTZ-Induced Seizures and Post-seizure Hallmarks of Early Epileptogenesis. Front Cell Neurosci 2020; 14:592374. [PMID: 33363455 PMCID: PMC7752812 DOI: 10.3389/fncel.2020.592374] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 11/16/2020] [Indexed: 12/22/2022] Open
Abstract
Both Fyn and tau have been associated with neuronal hyperexcitability and neurotoxicity in many tauopathies, including Alzheimer's disease (AD). Individual genetic ablation of fyn or tau appears to be protective against aberrant excitatory neuronal activities in AD and epilepsy models. It is, however, still unknown whether ablation of both Fyn and tau can likely elicit more profound anti-seizure and neuroprotective effects. Here, we show the effects of genetic deletion of Fyn and/or tau on seizure severity in response to pentylenetetrazole (PTZ)-induced seizure in mouse models and neurobiological changes 24 h post-seizures. We used Fyn KO (fyn -/-), tau KO (tau -/-), double knockout (DKO) (fyn -/- / tau -/-), and wild-type (WT) mice of the same genetic background. Both tau KO and DKO showed a significant increase in latency to convulsive seizures and significantly decreased the severity of seizures post-PTZ. Although Fyn KO did not differ significantly from WT, in response to PTZ, Fyn KO still had 36 ± 8% seizure reduction and a 30% increase in seizure latency compared to WT. Surprisingly, in contrast to WT, Fyn KO mice showed higher mortality in <20 min of seizure induction; these mice had severe hydrocephalous. None of the tau -/- and DKO died during the study. In response to PTZ, all KO groups showed a significant reduction in neurodegeneration and gliosis, in contrast to WT, which showed increased neurodegeneration [especially, parvalbumin (PV)-GABAergic interneurons] and gliosis. DKO mice had the most reduced gliosis. Immunohistochemically, phospho-tau (AT8, pS199/S202), Fyn expression, as well as Fyn-tau interaction as measured by PLA increased in WT post-PTZ. Moreover, hippocampal Western blots revealed increased levels of AT8, tyrosine phospho-tau (pY18), and phosphorylated Src tyrosine family kinases (pSFK) in PTZ-treated WT, but not in KO, compared to respective controls. Furthermore, PV interneurons were protected from PTZ-induced seizure effects in all KO mice. The levels of inwardly rectifying potassium (Kir 4.1) channels were also downregulated in astrocytes in the WT post-PTZ, while its levels did not change in KO groups. Overall, our results demonstrated the role of Fyn and tau in seizures and their impact on the mediators of early epileptogenesis in PTZ model.
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Affiliation(s)
- Marson Putra
- Neuroscience Interdepartmental Program, Iowa State University, Ames, IA, United States
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Sreekanth Puttachary
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Guanghao Liu
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, United States
| | - Gloria Lee
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, United States
| | - Thimmasettappa Thippeswamy
- Neuroscience Interdepartmental Program, Iowa State University, Ames, IA, United States
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
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7
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Dudek FE. Loss of GABAergic Interneurons in Seizure-Induced Epileptogenesis-Two Decades Later and in a More Complex World. Epilepsy Curr 2020; 20:70S-72S. [PMID: 33059465 PMCID: PMC7726724 DOI: 10.1177/1535759720960464] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- F Edward Dudek
- Department of Neurosurgery 14434University of Utah School of Medicine, USA
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8
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Bolshakov AP, Stepanichev MY, Dobryakova YV, Spivak YS, Markevich VA. Saporin from Saponaria officinalis as a Tool for Experimental Research, Modeling, and Therapy in Neuroscience. Toxins (Basel) 2020; 12:toxins12090546. [PMID: 32854372 PMCID: PMC7551693 DOI: 10.3390/toxins12090546] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/17/2020] [Accepted: 08/21/2020] [Indexed: 01/06/2023] Open
Abstract
Saporin, which is extracted from Saponaria officinalis, is a protein toxin that inactivates ribosomes. Saporin itself is non-selective toxin but acquires high specificity after conjugation with different ligands such as signaling peptides or antibodies to some surface proteins expressed in a chosen cell subpopulation. The saporin-based conjugated toxins were widely adopted in neuroscience as a convenient tool to induce highly selective degeneration of desired cell subpopulation. Induction of selective cell death is one of approaches used to model neurodegenerative diseases, study functions of certain cell subpopulations in the brain, and therapy. Here, we review studies where saporin-based conjugates were used to analyze cell mechanisms of sleep, general anesthesia, epilepsy, pain, and development of Parkinson’s and Alzheimer’s diseases. Limitations and future perspectives of use of saporin-based toxins in neuroscience are discussed.
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Affiliation(s)
- Alexey P. Bolshakov
- Laboratory of Molecular Neurobiology, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, 119991 Moscow, Russia;
- Correspondence:
| | - Mikhail Yu. Stepanichev
- Laboratory of Functional Biochemistry of the Nervous System, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, 119991 Moscow, Russia;
| | - Yulia V. Dobryakova
- Laboratory of Neurophysiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, 119991 Moscow, Russia; (Y.V.D.); (V.A.M.)
| | - Yulia S. Spivak
- Laboratory of Molecular Neurobiology, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, 119991 Moscow, Russia;
| | - Vladimir A. Markevich
- Laboratory of Neurophysiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, 119991 Moscow, Russia; (Y.V.D.); (V.A.M.)
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9
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Chun E, Bumanglag AV, Burke SN, Sloviter RS. Targeted hippocampal GABA neuron ablation by Stable Substance P-saporin causes hippocampal sclerosis and chronic epilepsy in rats. Epilepsia 2019; 60:e52-e57. [PMID: 30963545 DOI: 10.1111/epi.14723] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 02/24/2019] [Accepted: 03/15/2019] [Indexed: 11/29/2022]
Abstract
Cryptogenic temporal lobe epilepsy develops in the absence of identified brain injuries, infections, or structural malformations, and in these cases, an unidentified pre-existing abnormality may initiate febrile seizures, hippocampal sclerosis, and epilepsy. Although a role for GABAergic dysfunction in epilepsy is intuitively obvious, no causal relationship has been established. In this study, hippocampal GABA neurons were targeted for selective elimination to determine whether a focal hippocampal GABAergic defect in an otherwise normal brain can initiate cryptogenic temporal lobe epilepsy with hippocampal sclerosis. We used Stable Substance P-saporin conjugate (SSP-saporin) to target rat hippocampal GABA neurons, which selectively and constitutively express the neurokinin-1 receptors that internalize this neurotoxin. Bilateral and longitudinally extensive intrahippocampal microinjections of SSP-saporin caused no obvious behavioral effects for several days. However, starting ~4 days postinjection, rats exhibited episodes of immobilization, abnormal flurries of "wet-dog" shakes, and brief focal motor seizures characterized by facial automatisms and forepaw clonus. These clinically subtle behaviors stopped after ~4 days. Convulsive status epilepticus did not develop, and no deaths occurred. Months later, chronically implanted rats exhibited spontaneous focal motor seizures and extreme hippocampal sclerosis. These data suggest that hippocampal GABAergic dysfunction is epileptogenic and can produce the defining features of cryptogenic temporal lobe epilepsy.
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Affiliation(s)
- Eugene Chun
- Graduate Education in Biomedical Sciences Program, Morehouse School of Medicine, Atlanta, Georgia
| | | | - Sara N Burke
- Department of Neuroscience, University of Florida, Gainesville, Florida
| | - Robert S Sloviter
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia.,Department of Neurobiology, Morehouse School of Medicine, Atlanta, Georgia.,Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia
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10
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Chandrasekar A, Heuvel FO, Tar L, Hagenston AM, Palmer A, Linkus B, Ludolph AC, Huber-Lang M, Boeckers T, Bading H, Roselli F. Parvalbumin Interneurons Shape Neuronal Vulnerability in Blunt TBI. Cereb Cortex 2018; 29:2701-2715. [DOI: 10.1093/cercor/bhy139] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 04/20/2018] [Accepted: 05/17/2018] [Indexed: 12/25/2022] Open
Affiliation(s)
| | | | - Lilla Tar
- Department of Neurology, Ulm University, Ulm-DE, Germany
| | - Anna M Hagenston
- Department of Neurobiology—IZN, Heidelberg University, Heidelberg-DE, Germany
| | - Annette Palmer
- Department of Orthopedic trauma, Hand, Plastic and Reconstruction Surgery, Institute of Clinical and Experimental Trauma Immunology, Ulm University, Ulm-DE, Germany
| | - Birgit Linkus
- Department of Neurology, Ulm University, Ulm-DE, Germany
| | | | - Markus Huber-Lang
- Department of Orthopedic trauma, Hand, Plastic and Reconstruction Surgery, Institute of Clinical and Experimental Trauma Immunology, Ulm University, Ulm-DE, Germany
| | - Tobias Boeckers
- Department of Anatomy and Cell Biology, Ulm University, Ulm-DE, Germany
| | - Hilmar Bading
- Department of Neurobiology—IZN, Heidelberg University, Heidelberg-DE, Germany
| | - Francesco Roselli
- Department of Neurology, Ulm University, Ulm-DE, Germany
- Department of Orthopedic trauma, Hand, Plastic and Reconstruction Surgery, Institute of Clinical and Experimental Trauma Immunology, Ulm University, Ulm-DE, Germany
- Neurozentrum—Ulm University, Ulm-DE, Germany
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Enhanced expression of potassium-chloride cotransporter KCC2 in human temporal lobe epilepsy. Brain Struct Funct 2015; 221:3601-15. [PMID: 26427846 DOI: 10.1007/s00429-015-1122-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 09/23/2015] [Indexed: 12/19/2022]
Abstract
Synaptic reorganization in the epileptic hippocampus involves altered excitatory and inhibitory transmission besides the rearrangement of dendritic spines, resulting in altered excitability, ion homeostasis, and cell swelling. The potassium-chloride cotransporter-2 (KCC2) is the main chloride extruder in neurons and hence will play a prominent role in determining the polarity of GABAA receptor-mediated chloride currents. In addition, KCC2 also interacts with the actin cytoskeleton which is critical for dendritic spine morphogenesis, and for the maintenance of glutamatergic synapses and cell volume. Using immunocytochemistry, we examined the cellular and subcellular levels of KCC2 in surgically removed hippocampi of temporal lobe epilepsy (TLE) patients and compared them to control human tissue. We also studied the distribution of KCC2 in a pilocarpine mouse model of epilepsy. An overall increase in KCC2-expression was found in epilepsy and confirmed by Western blots. The cellular and subcellular distributions in control mouse and human samples were largely similar; moreover, changes affecting KCC2-expression were also alike in chronic epileptic human and mouse hippocampi. At the subcellular level, we determined the neuronal elements exhibiting enhanced KCC2 expression. In epileptic tissue, staining became more intense in the immunopositive elements detected in control tissue, and profiles with subthreshold expression of KCC2 in control samples became labelled. Positive interneuron somata and dendrites were more numerous in epileptic hippocampi, despite severe interneuron loss. Whether the elevation of KCC2-expression is ultimately a pro- or anticonvulsive change, or both-behaving differently during ictal and interictal states in a context-dependent manner-remains to be established.
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12
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Epilepsy and hippocampal neurodegeneration induced by glutamate decarboxylase inhibitors in awake rats. Epilepsy Res 2015; 116:27-33. [PMID: 26354164 DOI: 10.1016/j.eplepsyres.2015.06.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 06/15/2015] [Accepted: 06/17/2015] [Indexed: 11/20/2022]
Abstract
Glutamic acid decarboxylase (GAD), the enzyme responsible for GABA synthesis, requires pyridoxal phosphate (PLP) as a cofactor. Thiosemicarbazide (TSC) and γ-glutamyl-hydrazone (PLPGH) inhibit the free PLP-dependent isoform (GAD65) activity after systemic administration, leading to epilepsy in mice and in young, but not in adult rats. However, the competitive GAD inhibitor 3-mercaptopropionic acid (MPA) induces convulsions in both immature and adult rats. In the present study we tested comparatively the epileptogenic and neurotoxic effects of PLPGH, TSC and MPA, administered by microdialysis in the hippocampus of adult awake rats. Cortical EEG and motor behavior were analyzed during the next 2h, and aspartate, glutamate and GABA were measured by HPLC in the microdialysis-collected fractions. Twenty-four hours after drug administration rats were fixed for histological analysis of the hippocampus. PLPGH or TSC did not affect the motor behavior, EEG or cellular morphology, although the extracellular concentration of GABA was decreased. In contrast, MPA produced intense wet-dog shakes, EEG epileptiform discharges, a >75% reduction of extracellular GABA levels and remarkable neurodegeneration of the CA1 region, with >80% neuronal loss. The systemic administration of the NMDA glutamate receptor antagonist MK-801 30 min before MPA did not prevent the MPA-induced epilepsy but significantly protected against its neurotoxic effect, reducing neuronal loss to <30%. We conclude that in adult awake rats, drugs acting on PLP availability have only a weak effect on GABA neurotransmission, whereas direct GAD inhibition produced by MPA induces hyperexcitation leading to epilepsy and hippocampal neurodegeneration. Because this degeneration was prevented by the blockade of NMDA receptors, we conclude that it is due to glutamate-mediated excitotoxicity consequent to disinhibition of the hippocampal excitatory circuits.
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13
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Tangled roots: digging deeper into astrocyte or interneuron dysfunction in temporal lobe epilepsy. Epilepsy Curr 2011; 11:27-9. [PMID: 21852863 DOI: 10.5698/1535-7511-11.1.27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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GABAergic neuronal precursor grafting: implications in brain regeneration and plasticity. Neural Plast 2011; 2011:384216. [PMID: 21766042 PMCID: PMC3135013 DOI: 10.1155/2011/384216] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 04/11/2011] [Indexed: 12/20/2022] Open
Abstract
Numerous neurological disorders are caused by a dysfunction of the GABAergic system that impairs or either stimulates its inhibitory action over its neuronal targets. Pharmacological drugs have generally been proved very effective in restoring its normal function, but their lack of any sort of spatial or cell type specificity has created some limitations in their use. In the last decades, cell-based therapies using GABAergic neuronal grafts have emerged as a promising treatment, since they may restore the lost equilibrium by cellular replacement of the missing/altered inhibitory neurons or modulating the hyperactive excitatory system. In particular, the discovery that embryonic ganglionic eminence-derived GABAergic precursors are able to disperse and integrate in large areas of the host tissue after grafting has provided a strong rationale for exploiting their use for the treatment of diseased brains. GABAergic neuronal transplantation not only is efficacious to restore normal GABAergic activities but can also trigger or sustain high neuronal plasticity by promoting the general reorganization of local neuronal circuits adding new synaptic connections. These results cast new light on dynamics and plasticity of adult neuronal assemblies and their associated functions disclosing new therapeutic opportunities for the near future.
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King T, Qu C, Okun A, Mercado R, Ren J, Brion T, Lai J, Porreca F. Contribution of afferent pathways to nerve injury-induced spontaneous pain and evoked hypersensitivity. Pain 2011; 152:1997-2005. [PMID: 21620567 DOI: 10.1016/j.pain.2011.04.020] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Revised: 03/24/2011] [Accepted: 04/12/2011] [Indexed: 10/18/2022]
Abstract
A predominant complaint in patients with neuropathic pain is spontaneous pain, often described as burning. Recent studies have demonstrated that negative reinforcement can be used to unmask spontaneous neuropathic pain, allowing for mechanistic investigations. Here, ascending pathways that might contribute to evoked and spontaneous components of an experimental neuropathic pain model were explored. Desensitization of TRPV1-positive fibers with systemic resiniferatoxin (RTX) abolished spinal nerve ligation (SNL) injury-induced thermal hypersensitivity and spontaneous pain, but had no effect on tactile hypersensitivity. Ablation of spinal NK-1 receptor-expressing neurons blocked SNL-induced thermal and tactile hypersensitivity as well as spontaneous pain. After nerve injury, upregulation of neuropeptide Y (NPY) is observed almost exclusively in large-diameter fibers, and inactivation of the brainstem target of these fibers in the nucleus gracilis prevents tactile but not thermal hypersensitivity. Blockade of NPY signaling within the nucleus gracilis failed to block SNL-induced spontaneous pain or thermal hyperalgesia while fully reversing tactile hypersensitivity. Moreover, microinjection of NPY into nucleus gracilis produced robust tactile hypersensitivity, but failed to induce conditioned place aversion. These data suggest that spontaneous neuropathic pain and thermal hyperalgesia are mediated by TRPV1-positive fibers and spinal NK-1-positive ascending projections. In contrast, the large-diameter dorsal column projection can mediate nerve injury-induced tactile hypersensitivity, but does not contribute to spontaneous pain. Because inhibition of tactile hypersensitivity can be achieved either by spinal manipulations or by inactivation of signaling within the nucleus gracilis, the enhanced paw withdrawal response evoked by tactile stimulation does not necessarily reflect allodynia.
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Affiliation(s)
- Tamara King
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, USA
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16
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Ohira K, Hagihara H, Toyama K, Takao K, Kanai M, Funakoshi H, Nakamura T, Miyakawa T. Expression of tryptophan 2,3-dioxygenase in mature granule cells of the adult mouse dentate gyrus. Mol Brain 2010; 3:26. [PMID: 20815922 PMCID: PMC2945337 DOI: 10.1186/1756-6606-3-26] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Accepted: 09/05/2010] [Indexed: 12/20/2022] Open
Abstract
New granule cells are continuously generated in the dentate gyrus of the adult hippocampus. During granule cell maturation, the mechanisms that differentiate new cells not only describe the degree of cell differentiation, but also crucially regulate the progression of cell differentiation. Here, we describe a gene, tryptophan 2,3-dioxygenase (TDO), whose expression distinguishes stem cells from more differentiated cells among the granule cells of the adult mouse dentate gyrus. The use of markers for proliferation, neural progenitors, and immature and mature granule cells indicated that TDO was expressed in mature cells and in some immature cells. In mice heterozygous for the alpha-isoform of calcium/calmodulin-dependent protein kinase II, in which dentate gyrus granule cells fail to mature normally, TDO immunoreactivity was substantially downregulated in the dentate gyrus granule cells. Moreover, a 5-bromo-2'-deoxyuridine labeling experiment revealed that new neurons began to express TDO between 2 and 4 wk after the neurons were generated, when the axons and dendrites of the granule cells developed and synaptogenesis occurred. These findings indicate that TDO might be required at a late-stage of granule cell development, such as during axonal and dendritic growth, synaptogenesis and its maturation.
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Affiliation(s)
- Koji Ohira
- Division of Systems Medical Science, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake 470-1192, Japan
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17
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Calcagnotto ME, Zipancic I, Piquer-Gil M, Mello LE, Alvarez-Dolado M. Grafting of GABAergic precursors rescues deficits in hippocampal inhibition. Epilepsia 2010; 51 Suppl 3:66-70. [PMID: 20618404 DOI: 10.1111/j.1528-1167.2010.02613.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
gamma-Aminobutyric acid (GABA) has an important role in the mechanism of epilepsy. Cell grafts from different sources have been performed to modulate local circuits or increase GABAergic inhibition in animal models of epilepsy. Among the different transplanted cell types, the medial ganglionic eminence (MGE)-derived cells present the best properties to be used in cell-based therapy. In this work we review previous experiences with these cells. In addition, we present new evidence showing their ability to modulate the levels of inhibition in the host brain of mice with alterations in the GABAergic system, caused by the specific ablation of hippocampal interneurons. Grafted GFP(+) MGE-derived cells occupied the area of ablation and differentiated into mature NK-1-, SOM-, PV-, CR-, and NPY-expressing interneurons. Inhibitory postsynaptic current (IPSC) frequency and amplitude on CA1 pyramidal cells of the ablated hippocampus significantly increased after transplantation, reaching levels similar to controls. Our data strongly suggest the suitability of MGE-derived cells for the treatment of neurologic conditions for which an increase or modulation of synaptic inhibition is required.
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Affiliation(s)
- Maria E Calcagnotto
- Department of Cell Therapy and Regenerative Medicine, Andalusian Center for Molecular Biology and Regenerative Medicine CABIMER, Seville, Spain
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18
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Zipancic I, Calcagnotto ME, Piquer-Gil M, Mello LE, Álvarez-Dolado M. Transplant of GABAergic Precursors Restores Hippocampal Inhibitory Function in a Mouse Model of Seizure Susceptibility. Cell Transplant 2010; 19:549-64. [DOI: 10.3727/096368910x491383] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Defects in GABAergic function can cause epilepsy. In the last years, cell-based therapies have attempted to correct these defects with disparate success on animal models of epilepsy. Recently, we demonstrated that medial ganglionic eminence (MGE)-derived cells grafted into the neonatal normal brain migrate and differentiate into functional mature GABAergic interneurons. These cells are able to modulate the local level of GABA-mediated synaptic inhibition, which suggests their suitability for cell-based therapies. However, it is unclear whether they can integrate in the host circuitry and rescue the loss of inhibition in pathological conditions. Thus, as proof of principle, we grafted MGE-derived cells into a mouse model of seizure susceptibility caused by specific elimination of GABAergic interneuron subpopulations in the mouse hippocampus after injection of the neurotoxic saporin conjugated to substance P (SSP-Sap). This ablation was associated with significant decrease in inhibitory postsynaptic currents (IPSC) on CA1 pyramidal cells and increased seizure susceptibility induced by pentylenetetrazol (PTZ). Grafting of GFP+ MGE-derived cells in SSP-Sap-treated mice repopulates the hippocampal ablated zone with cells expressing molecular markers of mature interneurons. Interestingly, IPSC kinetics on CA1 pyramidal cells of ablated hippocampus significantly increased after transplantation, reaching levels similar to the normal mice. More importantly, this was associated with reduction in seizure severity and decrease in postseizure mortality induced by PTZ. Our data show that MGE-derived cells fulfill most of the requirements for an appropriate cell-based therapy, and indicate their suitability for neurological conditions where a modulation of synaptic inhibition is needed, such as epilepsy.
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Affiliation(s)
- I. Zipancic
- Department of Cell Therapy and Regenerative Medicine, Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER), Seville, Spain
- Centro de Investigación Príncipe Felipe (CIPF), Valencia, Spain
| | - M. E. Calcagnotto
- Department of Cell Therapy and Regenerative Medicine, Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER), Seville, Spain
| | - M. Piquer-Gil
- Department of Cell Therapy and Regenerative Medicine, Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER), Seville, Spain
| | - L. E. Mello
- Department of Physiology, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - M. Álvarez-Dolado
- Department of Cell Therapy and Regenerative Medicine, Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER), Seville, Spain
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19
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Göz D, Studholme K, Lappi DA, Rollag MD, Provencio I, Morin LP. Targeted destruction of photosensitive retinal ganglion cells with a saporin conjugate alters the effects of light on mouse circadian rhythms. PLoS One 2008; 3:e3153. [PMID: 18773079 PMCID: PMC2519834 DOI: 10.1371/journal.pone.0003153] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Accepted: 08/11/2008] [Indexed: 11/18/2022] Open
Abstract
Non-image related responses to light, such as the synchronization of circadian rhythms to the day/night cycle, are mediated by classical rod/cone photoreceptors and by a small subset of retinal ganglion cells that are intrinsically photosensitive, expressing the photopigment, melanopsin. This raises the possibility that the melanopsin cells may be serving as a conduit for photic information detected by the rods and/or cones. To test this idea, we developed a specific immunotoxin consisting of an anti-melanopsin antibody conjugated to the ribosome-inactivating protein, saporin. Intravitreal injection of this immunotoxin results in targeted destruction of melanopsin cells. We find that the specific loss of these cells in the adult mouse retina alters the effects of light on circadian rhythms. In particular, the photosensitivity of the circadian system is significantly attenuated. A subset of animals becomes non-responsive to the light/dark cycle, a characteristic previously observed in mice lacking rods, cones, and functional melanopsin cells. Mice lacking melanopsin cells are also unable to show light induced negative masking, a phenomenon known to be mediated by such cells, but both visual cliff and light/dark preference responses are normal. These data suggest that cells containing melanopsin do indeed function as a conduit for rod and/or cone information for certain non-image forming visual responses. Furthermore, we have developed a technique to specifically ablate melanopsin cells in the fully developed adult retina. This approach can be applied to any species subject to the existence of appropriate anti-melanopsin antibodies.
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Affiliation(s)
- Didem Göz
- Department of Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Keith Studholme
- Department of Psychiatry, Stony Brook University, Stony Brook, New York, United States of America
| | - Douglas A. Lappi
- Advanced Targeting Systems, San Diego, California, United States of America
| | - Mark D. Rollag
- Department of Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Ignacio Provencio
- Department of Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Lawrence P. Morin
- Department of Psychiatry, Stony Brook University, Stony Brook, New York, United States of America
- Program in Neuroscience, Medical Center, Stony Brook University, Stony Brook, New York, United States of America
- * E-mail:
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20
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Vasiliou AS, MacKenzie A, Morris R, McLaughlin L, Bubb VJ, Haddley K, Quinn JP. Generation of a transgenic model to address regulation and function of the human neurokinin 1 receptor (NK1R). Neuropeptides 2007; 41:195-205. [PMID: 17576012 DOI: 10.1016/j.npep.2007.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2007] [Revised: 03/16/2007] [Accepted: 04/25/2007] [Indexed: 11/24/2022]
Abstract
We have generated mouse transgenic lines using yeast artificial chromosome (YAC) technology which demonstrate expression from the human NK1 receptor (NK1R) locus. We introduced a 380 kb fragment encompassing the human NK1R gene and flanking regions which we hoped would recapitulate the expected endogenous expression of the human gene. To visualise this expression the NK1 locus co-expresses the green fluorescence protein gene (GFP) under the control of an internal ribosome entry site (IRES) sequence. We have generated five mouse lines that express the human NK1 receptor gene with and without the marker gene. All the lines incorporating the marker gene appear to exhibit the same expression pattern in analysis of selected anatomical regions throughout the mouse. The lack of a human specific NK1R antibody determined that we could not distinguish between expression of the transgene and endogenous NK1R. Our analysis has shown transgene expression in brain areas known to express NK1R in human such as the hippocampus and caudate putamen. The majority of these cells were also positive for GFP fluorescence. These transgenic lines may prove a good pre-clinical model as drugs can be addressed against both the human receptor and modulators of its expression in vivo.
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Affiliation(s)
- A S Vasiliou
- Physiology Laboratory, School of Biomedical Science, University of Liverpool L69 3BX, United Kingdom.
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21
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Wolansky T, Pagliardini S, Greer JJ, Dickson CT. Immunohistochemical characterization of substance P receptor (NK(1)R)-expressing interneurons in the entorhinal cortex. J Comp Neurol 2007; 502:427-41. [PMID: 17366610 DOI: 10.1002/cne.21338] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
It has been reported that application of substance P (SP) to the medial portion of the entorhinal cortex (EC) induces a powerful antiepileptic effect (Maubach et al. [1998] Neuroscience 83:1047-1062). This effect is presumably mediated via inhibitory interneurons expressing the neurokinin-1 receptor (NK(1)R), but the existence of NK(1)R-expressing inhibitory interneurons in the EC has not yet been reported. The present immunohistochemical study was performed in the rat to examine the existence and distribution of NK(1)R-expressing neurons in the EC as well as any co-expression of other neurotransmitters/neuromodulators known to be associated with inhibitory interneurons: gamma-aminobutyric acid (GABA), parvalbumin (PARV), calretinin (CT), calbindin (CB), somatostatin (SST), and neuropeptide Y (NPY). Our results indicated that NK(1)R-positive neurons were distributed rather sparsely (especially in the medial EC), primarily in layers II, V, and VI. The results of our double-immunohistochemical staining indicated that the vast majority of NK(1)R-expressing neurons also expressed GABA, SST, and NPY. In addition, CT was co-expressed in a weakly stained subgroup of NK(1)R-expressing neurons, and CB was co-expressed very rarely in the lateral EC, but not in the medial EC. In contrast, SP-immunopositive axons with fine varicosities were distributed diffusely throughout all layers of the EC, appearing to radiate from the angular bundle. SP may be released in a paracrine manner to activate a group of NK(1)R-expressing entorhinal neurons that co-express GABA, SST, and NPY, exerting a profound inhibitory influence on synchronized network activity in the EC.
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Affiliation(s)
- Trish Wolansky
- Centre for Neuroscience, University of Alberta, Edmonton, Alberta, Canada T6G 2R3
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22
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Wiley RG, Kline RH, Vierck CJ. Anti-nociceptive effects of selectively destroying substance P receptor-expressing dorsal horn neurons using [Sar9,Met(O2)11]-substance P-saporin: behavioral and anatomical analyses. Neuroscience 2007; 146:1333-45. [PMID: 17418497 DOI: 10.1016/j.neuroscience.2007.01.066] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2006] [Revised: 01/29/2007] [Accepted: 01/31/2007] [Indexed: 10/23/2022]
Abstract
Lumbar intrathecal injections of substance P-saporin (SP-sap) destroy dorsal horn neurons that express the neurokinin-1 receptor (NK-1R) resulting in decreased responses to a range of noxious stimuli and decreased hyperalgesia and allodynia. Forebrain injections of SP-sap produce considerable non-specific damage raising some concern about use of this toxin in vivo. The more stable and selective substance P congener, [Sar9,Met(O2)11]substance P coupled to saporin (SSP-sap) produces much more selective forebrain lesions at significantly lower doses. The present study sought to determine the anatomic and nocifensive behavioral effects of lumbar intrathecal injections of the more precisely targeted SSP-sap. On the basis of loss of lamina I NK-1R staining, lumbar intrathecal SSP-sap was seven times more potent than SP-sap and produced no loss of NK-1R expressing neurons in deeper laminae (III-VI or X). Transient decreases in hotplate responding occurred at 44 degrees C and 47 degrees C but not 52 degrees C during the first 3 weeks after SSP-sap injection with return to baseline by 4 weeks. Operant escape responses were reduced at 0.3 degrees C, 44 degrees C and 47 degrees C for at least 4 months. In the formalin test, SSP-sap also was about seven times more potent than SP-sap in reducing phase two behavior in both female Long Evans and male Sprague-Dawley rats. Both SSP-sap and SP-sap reduced formalin-induced FOS expression in deep and superficial laminae of the L4 dorsal horn in parallel with the reduction in phase 2 behavior. In summary, SSP-sap is highly effective in destroying lamina I NK-1R expressing neurons, without loss of deep NK-1R neurons. The behavioral effects of SSP-sap are similar to SP-sap suggesting that the antinociceptive effects of both toxins are indeed due to selective loss of NK-1R neurons in lamina I. SSP-sap is an attractive agent for possible treatment of chronic pain.
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MESH Headings
- Analgesics
- Animals
- Behavior, Animal/drug effects
- Conditioning, Operant/drug effects
- Data Interpretation, Statistical
- Escape Reaction/drug effects
- Female
- Formaldehyde
- Genes, fos/drug effects
- Hot Temperature
- Immunohistochemistry
- Injections, Spinal
- Male
- Pain Measurement/drug effects
- Posterior Horn Cells/drug effects
- Posterior Horn Cells/metabolism
- Posterior Horn Cells/ultrastructure
- Rats
- Rats, Long-Evans
- Rats, Sprague-Dawley
- Reaction Time/drug effects
- Receptors, Neurokinin-1/biosynthesis
- Receptors, Neurokinin-1/metabolism
- Recombinant Fusion Proteins/pharmacology
- Ribosome Inactivating Proteins, Type 1
- Saporins
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Affiliation(s)
- R G Wiley
- Laboratory of Experimental Neurology, VA TVHS, Nashville, TN 37212-2637, USA.
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23
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Mowla A, Ashkani H, Firozabadi A, Ghanizadeh A, Chohedri H, Pani A, Gorman JM. Relief of acute intractable traumatic pain with ECT. J Psychiatr Pract 2007; 13:55-7. [PMID: 17242594 DOI: 10.1097/00131746-200701000-00009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Arash Mowla
- Shiraz University of Medical Sciences, Shiraz, Iran
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24
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Tang FR, Chia SC, Jiang FL, Ma DL, Chen PM, Tang YC. Calcium binding protein containing neurons in the gliotic mouse hippocampus with special reference to their afferents from the medial septum and the entorhinal cortex. Neuroscience 2006; 140:1467-79. [PMID: 16650619 DOI: 10.1016/j.neuroscience.2006.03.022] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2005] [Revised: 03/06/2006] [Accepted: 03/12/2006] [Indexed: 11/26/2022]
Abstract
In CA1 area and the hilus of the dentate gyrus of the mouse hippocampus, drastic reduction of NeuN, calbindin, calretinin, or parvalbumin immunopositive neurons was shown at 3, 7 and 60 days after pilocarpine-induced status epilepticus. In gliotic CA1 area at 60 days, few dendritic branches of calcium binding protein immunopositive neurons could be found suggesting reorganization of the afferents of surviving calcium binding protein immunopositive neurons. Calbindin, calretinin, or parvalbumin and 5-bromo-2'-deoxyuridine (BrdU) double labeling showed that calcium binding protein immunopositive neurons in gliotic CA1 area at 60 days were surviving instead of newly generated neurons. Iontophoretic injection of Phaseolus vulgaris leucoagglutinin into the medial septum and the nucleus of the diagonal band of Broca or the lateral entorhinal cortex showed contacts between Phaseolus vulgaris leucoagglutinin immunopositive en passant and terminal boutons and surviving calcium binding protein immunopositive neurons in the hippocampus. The presence in the gliotic hippocampus of enlarged and/or aggregated bouton-like structures 60 days after pilocarpine-induced status epilepticus is indicative for the reorganization of connections between the hippocampal afferents and surviving hippocampal neurons. This reconstruction could be a factor in the ongoing epileptic activity in this model of mesial temporal lobe epilepsy.
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Affiliation(s)
- F R Tang
- Epilepsy Research Laboratory, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore 308433.
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25
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Gris D, Marsh DR, Dekaban GA, Weaver LC. Comparison of effects of methylprednisolone and anti-CD11d antibody treatments on autonomic dysreflexia after spinal cord injury. Exp Neurol 2005; 194:541-9. [PMID: 15890340 DOI: 10.1016/j.expneurol.2005.03.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2005] [Revised: 03/24/2005] [Accepted: 03/31/2005] [Indexed: 10/25/2022]
Abstract
Autonomic dysreflexia is a condition of episodic hypertension that develops after spinal cord injury (SCI). We previously showed that a two-day anti-inflammatory treatment with an anti-CD11d integrin monoclonal antibody (mAb), soon after SCI in rats, reduced the magnitude of dysreflexia for at least 6 weeks. Effects of methylprednisolone (MP), a commonly used neuroprotective treatment for SCI, on dysreflexia have never been examined. We compared the effects of a 2-day MP treatment and/or the anti-CD11d mAb on autonomic dysreflexia, elicited by colon distension, after clip-compression SCI at the 4th thoracic segment (T4) in rats. We assessed the effects of each treatment on the size of the calcitonin gene-related peptide (CGRP)-immunoreactive afferent arbour in the dorsal horn, as changes in this arbour can correlate with the development of dysreflexia. MP reduced autonomic dysreflexia by approximately 50% at 2 weeks after SCI, but this effect was lost by 6 weeks. At 2 weeks, the combined effects of MP and the mAb were not additive, reducing dysreflexia by approximately 50%. Neither MP nor the mAb treatment altered the area of CGRP-immunoreactive fibres in the lumbar cord, the crucial input region for dysreflexia initiated by colon distension. However, both treatments led to increased fibre areas in the T9 segment, correlated with greater tissue integrity and smaller lesions, delineated by inflammatory cells. In summary, MP only temporarily decreases autonomic dysreflexia after SCI. The early beneficial effects of both treatments on dysreflexia do not relate to changes in the CGRP-immunoreactive afferent arbour but may correlate with decreased lesion progression.
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Affiliation(s)
- Denis Gris
- Spinal Cord Injury Team, Laboratory of Spinal Cord Injury, BioTherapeutics Research Group, Robarts Research Institute and Graduate Program in Neuroscience, University of Western Ontario, 100 Perth Drive, London, Ontario, Canada N6A 5K8
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26
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Maglóczky Z, Freund TF. Impaired and repaired inhibitory circuits in the epileptic human hippocampus. Trends Neurosci 2005; 28:334-40. [PMID: 15927690 DOI: 10.1016/j.tins.2005.04.002] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2005] [Revised: 03/14/2005] [Accepted: 04/08/2005] [Indexed: 10/25/2022]
Abstract
This review focuses on the epileptic human temporal lobe, primarily on recent findings related to changes in hippocampal GABAergic interneuron circuits that have a central role in epileptogenesis. Relying on correlations to animal studies, we provide a functional interpretation of the different changes in perisomatic inhibition (controlling output synchrony) and dendritic inhibition (controlling input plasticity), and the potential consequences of the loss of interneuron-selective interneurons. The highly heterogeneous, but specific, alterations of GABAergic interneuron circuits have important implications for the pharmacotherapy of epilepsy.
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Affiliation(s)
- Zsófia Maglóczky
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, POB 67, H-1450, Hungary
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27
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Chiken S, Tokuno H. Impairment of skilled forelimb use after ablation of striatal interneurons expressing substance P receptors in rats: an analysis using a pasta matrix reaching task. Exp Brain Res 2005; 162:532-6. [PMID: 15754181 DOI: 10.1007/s00221-004-2189-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2004] [Accepted: 11/03/2004] [Indexed: 10/25/2022]
Abstract
Local injection of substance P (SP)-saporin can cause selective ablation of striatal interneurons expressing SP receptors (SPR). In this study, we evaluated quantitatively the impairment of skilled forelimb use after unilateral ablation of the striatal interneurons using a pasta matrix reaching task in rats. We found a significant decrease of the number of the pasta pieces (uncooked spaghetti) retrieved using the paw of the experimental side contralateral to the ablation, whereas the number of the pasta pieces retrieved using the paw of the intact side increased significantly. These findings, with our previous reports, suggest that the modulation of the cortico-striato-entopeduncular direct pathway by striatal interneurons is important for maintaining normal basal-ganglia control for skilled forelimb movements.
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Affiliation(s)
- Satomi Chiken
- Department of Brain Structure, Tokyo Metropolitan Institute for Neuroscience, Fuchu, 183-8526 Tokyo, Japan
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28
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Harvey BD, Sloviter RS. Hippocampal granule cell activity and c-Fos expression during spontaneous seizures in awake, chronically epileptic, pilocarpine-treated rats: Implications for hippocampal epileptogenesis. J Comp Neurol 2005; 488:442-63. [PMID: 15973680 DOI: 10.1002/cne.20594] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The process of postinjury hippocampal epileptogenesis may involve gradually developing dentate granule cell hyperexcitability caused by neuron loss and synaptic reorganization. We tested this hypothesis by repeatedly assessing granule cell excitability after pilocarpine-induced status epilepticus (SE) and monitoring granule cell behavior during 235 spontaneous seizures in awake, chronically implanted rats. During the first week post-SE, granule cells exhibited diminished paired-pulse suppression and decreased seizure discharge thresholds in response to afferent stimulation. Spontaneous seizures often began during the first week after SE, recruited granule cell discharges that followed behavioral seizure onsets, and evoked c-Fos expression in all hippocampal neurons. Paired-pulse suppression and epileptiform discharge thresholds increased gradually after SE, eventually becoming abnormally elevated. In the chronic epileptic state, interictal granule cell hyperinhibition extended to the ictal state; granule cells did not discharge synchronously before any of 191 chronic seizures. Instead, granule cells generated only low-frequency voltage fluctuations (presumed "field excitatory postsynaptic potentials") during 89% of chronic seizures. Granule cell epileptiform discharges were recruited during 11% of spontaneous seizures, but these occurred only at the end of each behavioral seizure. Hippocampal c-Fos after chronic seizures was expressed primarily by inhibitory interneurons. Thus, granule cells became progressively less excitable, rather than hyperexcitable, as mossy fiber sprouting progressed and did not initiate the spontaneous behavioral seizures. These findings raise doubts about dentate granule cells as a source of spontaneous seizures in rats subjected to prolonged SE and suggest that dentate gyrus neuron loss and mossy fiber sprouting are not primary epileptogenic mechanisms in this animal model.
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Affiliation(s)
- Brian D Harvey
- Department of Pharmacology, University of Arizona College of Medicine, Tucson, Arizona 85724, USA
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29
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Yezierski RP, Yu CG, Mantyh PW, Vierck CJ, Lappi DA. Spinal neurons involved in the generation of at-level pain following spinal injury in the rat. Neurosci Lett 2004; 361:232-6. [PMID: 15135936 DOI: 10.1016/j.neulet.2003.12.035] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Using a conjugate of substance P and the ribosome-inactivating protein saporin, neurons expressing the neurokinin-1 receptor in lamina I of the spinal cord were targeted to determine their role in the expression of a spontaneous pain behavior following intraspinal injections of quisqualic acid in the rat. Treatment was carried out at the time of injury in order to prevent the onset of the behavior, and following onset in order to evaluate the potential clinical utility of this intervention. Treatment at the time of injury resulted in significant decreases in onset-time and severity of pain behavior, while treatment at the time of onset led to a significant reduction of the spontaneous self-directed behavior. The results suggest that the substrate for at-level pain following spinal cord injury includes a population of spinal neurons expressing the neurokinin-1 receptor in the superficial laminae of the spinal cord.
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Affiliation(s)
- Robert P Yezierski
- Department of Orthodontics, University of Florida, Gainesville, FL 32610, USA.
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Abstract
Three cases are presented in which electroconvulsive therapy (ECT) for depression led to the relief of comorbid complex regional pain syndrome as well as depression. In one of the cases, concomitant fibromyalgia was not relieved during 2 separate series of ECT. The literature regarding the role of ECT in the management of chronic pain is reviewed and discussed in light of recent findings about ECT and changes in neurotransmission associated with seizures.
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Affiliation(s)
- William W McDaniel
- Department of Psychiatry and Behavioral Sciences, Eastern Virginia Medical School, Norfolk, VA 23507, USA.
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Levita L, Mania I, Rainnie DG. Subtypes of substance P receptor immunoreactive interneurons in the rat basolateral amygdala. Brain Res 2003; 981:41-51. [PMID: 12885424 DOI: 10.1016/s0006-8993(03)02870-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Local injections of the neurotoxin SP-saporin into the basolateral amygdala (BLA) are reported to specifically lesion substance P receptor immunoreactive (SPR-IR) interneurons, and to reduce anxiety related behavior. Hence, this technique might provide a means to study how defined interneuron populations regulate neuronal activity in the BLA. However, what interneuron subgroups in the BLA might be targeted by SP-saporin lesions has not been established. This study has used dual-labeling immunofluorescence in the rat BLA to examine SPR-IR neurons for their colocalization with the calcium-binding proteins; calbindin-D28k (CB), parvalbumin (PV), and calretinin (CR); and the neuropeptides somatostatin (SOM) and neuropeptide Y (NPY). We found that all NPY-IR neurons and 45% of SOM-IR interneurons expressed SPR-IR, and that 50% and 51% of the SPR-IR interneuron population expressed NPY- and SOM-IR, respectively. Previous studies have reported that approximately a third of SOM-IR interneurons also express NPY, which suggests a large degree of overlap between the NPY, SOM and SPR expressing neurons in the BLA. We also found that the majority of SPR-IR cells were CB-IR (62%), but that these interneurons represented only 2.8% of the total CB-IR population. Moreover, SPR-IR interneurons did not express either PV-or CR- IR. Hence, SP-saporin lesions would ablate all interneurons in the BLA that contain NPY, but leave the majority of the CB-IR cells intact, and have no effect on the CR- and PV-IR populations. Consequently, these results support the use of SP-saporin lesions as a useful technique to study the role of NPY-IR interneurons in the BLA.
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Affiliation(s)
- Liat Levita
- Department of Psychiatry and Behavioral Sciences, Emory University, Woodruff Memorial Building, 1639 Pierce Drive, Rm. 4000, Atlanta, GA 30322, USA.
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Affiliation(s)
- Thomas Brewer
- School of Nursing, University of Connecticut, Storrs, USA.
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Sarntinoranont M, Iadarola MJ, Lonser RR, Morrison PF. Direct interstitial infusion of NK1-targeted neurotoxin into the spinal cord: a computational model. Am J Physiol Regul Integr Comp Physiol 2003; 285:R243-54. [PMID: 12793999 DOI: 10.1152/ajpregu.00472.2002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Convection-enhanced delivery of substance P (SP) nocitoxins to the spinal cord interstitium is under consideration for the treatment of chronic pain. To characterize treatment protocols, a three-dimensional finite-element model of infusion into the human dorsal column was developed to predict the distribution of SP-diphtheria toxin fusion protein (SP-DT') within normal and target tissue. The model incorporated anisotropic convective and diffusive transport through the interstitial space, hydrolysis by peptidases, and intracellular trafficking. For constant SP-DT' infusion (0.1 microl/min), the distribution of cytotoxicity in NK1 receptor-expressing neurons was predicted to reach an asymptotic limit at 6-8 h in the transverse direction at the level of the infusion cannula tip ( approximately 60% ablation of target neurons in lamina I/II). Computations revealed that SP-DT' treatment was favored by a stable SP analog (half-life approximately 60 min), high infusate concentration (385 nM), and careful catheter placement (adjacent to target lamina I/II). Sensitivity of cytotoxic regions to NK1 receptor density and white matter protease activity was also established. These data suggest that intraparenchymal infusions can be useful for treatment of localized chronic pain.
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Affiliation(s)
- Malisa Sarntinoranont
- Drug Delivery and Kinetics Resource, Div. of Bioengineering and Physical Science, ORS, NIH, Bldg. 13, Rm. 3N17, 13 South Dr., Bethesda, MD 20892-5766, USA.
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Saka E, Iadarola M, Fitzgerald DJ, Graybiel AM. Local circuit neurons in the striatum regulate neural and behavioral responses to dopaminergic stimulation. Proc Natl Acad Sci U S A 2002; 99:9004-9. [PMID: 12060713 PMCID: PMC124413 DOI: 10.1073/pnas.132212499] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2002] [Indexed: 11/18/2022] Open
Abstract
Interneurons are critical for shaping neuronal circuit activity in many parts of the central nervous system. To study interneuron function in the basal ganglia, we tested and characterized an NK-1 receptor-based method for targeted ablation of specific classes of interneuron in the striatum. Our findings demonstrate that the neurotoxin SP-PE35, a substance P-Pseudomonas exotoxin conjugate, selectively targets striatal cholinergic and nitric oxide synthase/somatostatinergic interneurons when injected locally into the striatum. The effects of this selective cell targeting encompassed alterations in both behavioral and neural responses to dopaminergic stimulation, including altered patterns of early-gene response in striosomes and matrix. We conclude that NK-1-bearing local circuit neurons of the striatum regulate the differential responses of striatal projection neurons to dopamine-mediated signaling.
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Affiliation(s)
- E Saka
- Department of Brain and Cognitive Sciences and The McGovern Institute for Brain Research, Massachusetts Institute of Technology, E25-618, 45 Carleton Street, Cambridge, MA 02139, USA
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Zappone CA, Sloviter RS. Commissurally projecting inhibitory interneurons of the rat hippocampal dentate gyrus: a colocalization study of neuronal markers and the retrograde tracer Fluoro-gold. J Comp Neurol 2001; 441:324-44. [PMID: 11745653 DOI: 10.1002/cne.1415] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Improved methods for detecting neuronal markers and the retrograde tracer Fluoro-Gold (FG) were used to identify commissurally projecting neurons of the rat hippocampus. In addition to the dentate hilar mossy cells and CA3 pyramidal cells shown previously to transport retrograde tracers after injection into the dorsal hippocampus, FG-positive interneurons of the dentate granule cell layer and hilus were detected in numbers greater than previously reported. FG labeling of interneurons was variable among animals, but was as high as 96% of hilar somatostatin-positive interneurons, 84% of parvalbumin-positive cells of the granule cell layer and hilus combined, and 33% of hilar calretinin-positive cells. By comparison, interneurons of the dentate molecular layer and all hippocampal subregions were conspicuously FG-negative. Whereas hilar mossy cells and CA3 pyramidal cells were FG-labeled throughout the longitudinal axis, FG-positive interneurons exhibited a relatively homotopic distribution. "Control" injections of FG into the neocortex, septum, and ventral hippocampus demonstrated that the homotopic labeling of dentate interneurons was injection site-specific, and that the CA1-CA3 interneurons unlabeled by contralateral hippocampal FG injection were nonetheless able to transport FG from the septum. These data suggest a hippocampal organizing principle according to which virtually all commissurally projecting hippocampal neurons share the property of being monosynaptic targets of dentate granule cells. Because granule cells innervate their exclusively ipsilateral target cells in a highly lamellar pattern, these results suggest that focal granule cell excitation may result in commissural inhibition of the corresponding "twin" granule cell lamella, thereby lateralizing and amplifying the influence of the initiating discharge.
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Affiliation(s)
- C A Zappone
- Department of Pharmacology, University of Arizona College of Medicine, 1501 N. Campbell Avenue, Tucson, AZ 85724, USA
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