Cochlear Morphology of the Audiogenic-Seizure Susceptible (Ags) Or Genetically Epilepsy Prone Rat (Gepr)

Penny, J. E.; Hodges, Kurt; Kupetz, S A; Glenn, D W; Jobe, P C

doi:10.3109/00016488309130909

Cited by 40 publications

(15 citation statements)

References 17 publications

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“…Although a number of studies have investigated morphologic (82–84), electrophysiologic (85–87), pharmacologic (88–89), and biochemical (90–92) abnormalities associated with seizure susceptibility in auditory and nonauditory brainstem nuclei in a variety of genetic audiogenic seizures models, most do not describe the possible role that auditory brainstem nuclei may play in the neuronal network for audiogenic seizures (46,93). The genetically epilepsy‐prone rat (GEPR) is an animal model that exhibits generalized tonic–clonic seizures when exposed to sound stimulation (94).…”

Section: Discussionmentioning

confidence: 99%

Morphologic and Neurochemical Abnormalities in the Auditory Brainstem of the Genetically Epilepsy‐prone Hamster (GPG/Vall)

et al. 2005

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Summary:Purpose: This study was performed to evaluate whether audiogenic seizures, in a strain of genetically epilepsyprone hamsters (GPG/Vall), might be associated with morphologic alterations in the cochlea and auditory brainstem. In addition, we used parvalbumin as a marker of neurons with high levels of activity to examine changes within neurons.Methods: Cochlear histology as well as parvalbumin immunohistochemistry were performed to assess possible abnormalities in the GPG/Vall hamster. Densitometry also was used to quantify levels of parvalbumin immunostaining within neurons and fibers in auditory nuclei.Results: In the present study, missing outer hair cells and spiral ganglion cells were observed in the GPG/Vall hamster. In addition, an increase was noted in the size of spiral ganglion cells as well as a decrease in the volume and cell size of the cochlear nucleus (CN), the superior olivary complex nuclei (SOC), and the nuclei of the lateral lemniscus (LL) and the inferior colliculus (IC). These alterations were accompanied by an increase in levels of parvalbumin immunostaining within CN, SOC, and LL neurons, as well as within parvalbumin-immunostained fibers in the CN and IC.Conclusions: These data are consistent with a cascade of atrophic changes starting in the cochlea and extending along the auditory brainstem in an animal model of inherited epilepsy. Our data also show an upregulation in parvalbumin immunostaining in the neuropil of the IC that may reflect a protective mechanism to prevent cell death in the afferent sources to this nucleus. Key Words: Calcium-binding protein-AGS-Animal model-Hamster.Animal models of inherited epilepsy are essential to understand the origin of epileptic seizures because they represent an abnormal nervous system and reproduce the mechanisms of hyperexcitability than occur in nature (1). In numerous species, including rat (2,3), mouse (4,5), gerbil (6), and baboon (7), genetic models of epilepsy are available. In these models, several steps have been identified in the cascade leading from seizure-activity episodes to long-lasting and quasi-permanent modifications of the neuronal circuitry organization. These include neuron atrophy (8), cell death (9), neuronal degeneration (10), synaptic rearrangement (11), abnormalities in the expression of neurotransmitters and/or their receptors (12)(13)(14), and changes in intracellular signaling pathways in which calcium-related mechanisms are involved (15-17).

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Section: Discussionmentioning

confidence: 99%

Morphologic and Neurochemical Abnormalities in the Auditory Brainstem of the Genetically Epilepsy‐prone Hamster (GPG/Vall)

et al. 2005

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“…This characteristic is common in many rodents exhibiting audiogenic seizures [83,84]. These animals tend to show a reduction in their ABR response latencies, even to stimulations at 8 kHz, which is the optimal frequency for hearing in rats and most rodents [85].…”

Section: Abrmentioning

confidence: 99%

The genetic audiogenic seizure hamster from Salamanca: The GASH:Sal

Muñoz

Carballosa-Gautam

Yanowsky

et al. 2017

Epilepsy & Behavior

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The hamster has been previously described as a paroxysmal dystonia model, but our strain is currently recognized as a model of audiogenic seizures (AGS). The original first epileptic hamster appeared spontaneously at the University of Valladolid, where it was known as the GPG:Vall line, and was transferred to the University of Salamanca where a new strain was developed, named GASH:Sal. By testing auditory brainstem responses, the GASH:Sal exhibits elevated auditory thresholds that indicate a hearing impairment. Moreover, amplified fragment length polymorphism analysis distinguished genetic differences between the susceptible GASH:Sal hamster strain and the control Syrian hamsters. The GASH:Sal constitutes an experimental model of reflex epilepsy of audiogenic origin derived from an autosomal recessive disorder. Thus, the GASH:Sal exhibits generalized tonic-clonic seizures, characterized by a short latency period after auditory stimulation, followed by wild running, a convulsive phase, and finally stupor, with origin in the brainstem. The seizure profile of the GASH:Sal is similar to those exhibited by other models of inherited AGS susceptibility, which decreases after six months of age, but the proneness across generations is maintained. The GASH:Sal can be considered a reliable model of audiogenic seizures, suitable to investigate current antiepileptic pharmaceutical treatments as well as novel therapeutic drugs.This article is part of a Special Issue entitled Genetic Models-Epilepsy.

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“…Extensive work has been done on the nature of audiogenic seizures in the GEPR; pathology has been observed in both peripheral (Penny et al, 1983) and central auditory regions which apparently culminates in decreased functional inhibition in the central nucleus of the inferior colliculus (Faingold et al, 1986a,b). Development of audiogenic seizures in GEPRs has also been studied (Hjeresen et al, 1987).…”

mentioning

confidence: 98%

Developing Genetically Epilepsy‐Prone Rats Have an Abnormal Seizure Response to Flurothyl

1989

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Development of clonic-tonic flurothyl-induced seizures was examined in both normal and genetically epilepsy-prone rats (GEPRs). At each age, from 10 to 30 days, clonus occurred at significantly shorter latencies in GEPRs than in normal rats. The latency to onset of clonic seizures did not change with age, however, in either GEPRs or normal rats. A different pattern of response was observed in the progression to tonic seizures. As normal animals matured, the latency to tonic seizures became longer and, by day 30, the duration of flurothyl exposure necessary to induce tonus was almost 70% greater in normal rats than in the GEPRs. In contrast, in GEPRs, tonic extension occurred immediately following the onset of clonus throughout development. A subset of GEPRs failed to have audiogenic seizures in a 40-day posttest. These animals had a flurothyl response identical to their audiogenic-susceptible litter mates. These data suggest that (a) a protective mechanism which develops against tonic seizures in normal rats fails to mature in the GEPR, and (b) seizure inducing gene-linked neural abnormalities occur in the GEPR independent of pathologies underlying audiogenic seizures.

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Cochlear Morphology of the Audiogenic-Seizure Susceptible (Ags) Or Genetically Epilepsy Prone Rat (Gepr)

Cited by 40 publications

References 17 publications

Morphologic and Neurochemical Abnormalities in the Auditory Brainstem of the Genetically Epilepsy‐prone Hamster (GPG/Vall)

Morphologic and Neurochemical Abnormalities in the Auditory Brainstem of the Genetically Epilepsy‐prone Hamster (GPG/Vall)

The genetic audiogenic seizure hamster from Salamanca: The GASH:Sal

Developing Genetically Epilepsy‐Prone Rats Have an Abnormal Seizure Response to Flurothyl

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