Hippocampal transection attenuates kainic acid-induced amygdalar seizures in rats

Imamura, Shin ichi; Tanaka, Shigeya; Akaike, Koichi; Tojo, Hideshi; Takigawa, Morikuni; Kuratsu, Jun Ichi

doi:10.1016/s0006-8993(01)02098-4

Cited by 19 publications

(7 citation statements)

References 25 publications

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“…Seizure propagation can be suppressed by transection surgery between the dorsal and ventral hippocampus in a KA-induced rat epilepsy model. 12) However, hippocampal blockade by DBS in our study failed to reduce the frequency of seizures. Bilateral hippocampal lesioning by ibotenic acid injection delays the development of amygdala kindling, but fails to prevent secondary generalization of the seizure.…”

Section: Discussioncontrasting

confidence: 66%

Epileptic Focus Stimulation and Seizure Control in the Rat Model of Kainic Acid-Induced Limbic Seizures

Urino

Hashizume

Maehara

et al. 2010

Neurol. Med. Chir.(Tokyo)

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The inhibitory effects of deep brain stimulation (DBS) were investigated in a rat model of kainic acid (KA)-induced limbic status epilepticus. Wistar rats were injected with 1.0 mg KA into the left amygdala after stereotactic implantation of a guide cannula and electrodes. Bipolar rectangular pulses of 0.1 msec duration and 0.1-0.3 mA amplitude were applied intermittently to the left amygdala (10 Hz or 130 Hz), left ventral hippocampus (10 Hz), and left dorsomedial thalamus (130 Hz). Seizure frequency was evaluated by video electroencephalography monitoring and compared to control animals that did not receive DBS. All rats developed limbic status epilepticus 60-90 minutes after KA injection. Seizure frequency was significantly reduced by 10 Hz stimulation of the amygdala and by 130 Hz stimulation of the dorsomedial thalamus. No significant effects were observed with other types of stimulation. Seizure behaviors or duration of seizure were not changed significantly by DBS treatment. DBS of an epileptic focus may attenuate KA-induced limbic seizures, depending on the stimulation sites and parameters.

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Section: Discussioncontrasting

confidence: 66%

Epileptic Focus Stimulation and Seizure Control in the Rat Model of Kainic Acid-Induced Limbic Seizures

Urino

Hashizume

Maehara

et al. 2010

Neurol. Med. Chir.(Tokyo)

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“…The efficacy of hippocampal transections in controlling seizures in animal models of temporal lobe epilepsy has been studied [10, 11], but the safety of such transections with regard to memory functioning has not been investigated. In this study, we have shown that unilateral and bilateral cuts of the CA3 layer did not affect NOR and MWM scores in rats, suggesting that memory processing necessary for these tasks does not require intact transmission throughout the whole length of this pyramidal cell layer.…”

Section: Discussionmentioning

confidence: 99%

“…This effect could be attributed directly to the removal of recurrent excitation. Moreover, hippocampal transections have been shown to control kainic acid-induced seizures in rats [10] and mice [11], without assessment of the effect of such transections on memory. In this study, we intended to assess the effect of unilateral and bilateral CA3 transections on memory function in rats.…”

Section: Introductionmentioning

confidence: 99%

Transection of CA3 does not affect memory performance in rats

Koubeissi

Rashid

Casadesús

et al. 2011

Epilepsy & Behavior

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Longitudinal hippocampal pathways are needed for seizure synchronization, and there is evidence that their transection may abolish seizures. However, the effect of such transection on memory is unknown. In this study, we investigated the effect of transverse CA3 transections on memory function in Sprague-Dawley rats. Using a stereotactic knife, a single CA3 transection was made unilaterally (n=5) or bilaterally (n=5). Sham surgery was done in another group (n=4). Morris water maze (MWM) and Novel object recognition (NOR) tests were started 18 days later revealing no significant differences between transected animals and controls. Cresyl-violet brain staining confirmed the locations of transections in the CA3 region. We conclude that normal performance in MWM and NOR tests does not appear to require intact transmission throughout the whole length of CA3, supporting the hypothesis that CA3 transections may be used in temporal lobe epilepsy to interrupt seizure circuitry while preserving memory.

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“…Although the role of the VH in the generation of epileptiform activity (EA) is significant, the importance of connections between DH and VH for full seizure development should not be underestimated. Recent clinical and basic research studies show that hippocampal longitudinal synchrony of EA is required for seizure generation and transection of the hippocampal longitudinal epileptic circuits is effective in suppressing seizures (Imamura et al, 2001; Shimizu et al, 2006; Umeoka et al, 2012). However the premise for the increase of hippocampal longitudinal synchronization in epileptic brain is not fully understood.…”

Section: Introductionmentioning

confidence: 99%

Status epilepticus results in region-specific alterations in seizure susceptibility along the hippocampal longitudinal axis

Isaeva¹,

Romanov²,

Holmes³

et al. 2015

Epilepsy Research

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Temporal lobe epilepsy (TLE) is the most common epilepsy syndrome in adults. In particular, the hippocampus is highly susceptible to abnormal synchronization. Recent advances in the surgical treatment of patients with refractory TLE have shown that multiple hippocampal transections can effectively control seizures. It has been suggested that in TLE the synchrony in the longitudinal connections is required for seizure generation; however the physiological background for the increase in hippocampal synchronization along the longitudinal axis is not fully understood. The hippocampus varies in seizure susceptibility along its longitudinal axis with the ventral hippocampus (VH) region being more seizure-prone and susceptible to neuronal damage than the dorsal hippocampus (DH). In the present study we studied seizure susceptibility along the longitudinal axis of the hippocampus following pilocarpine-induced status epilepticus (SE). In control conditions the VH generates epileptiform activity (EA) more frequently than the DH when exposed to a low Mg2+/1Ca2+/5K+ solution. Following SE the probability of inducing epileptiform actvitiy (EA) is similar in the VH and DH slices. This SE-induced change is due to an increase in the proportion of DH slices responding to the low Mg2+/1Ca2+/5K+ solution with EA. Moreover, both the VH and DH show similar responses to a low Mg2+/1Ca2+/5K+ solution. These findings indicate that the hippocampus undergoes significant functional changes following SE, which may provide the necessary increase of synchrony along the longitudinal axis to generate seizures in TLE.

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Hippocampal transection attenuates kainic acid-induced amygdalar seizures in rats

Cited by 19 publications

References 25 publications

Epileptic Focus Stimulation and Seizure Control in the Rat Model of Kainic Acid-Induced Limbic Seizures

Epileptic Focus Stimulation and Seizure Control in the Rat Model of Kainic Acid-Induced Limbic Seizures

Transection of CA3 does not affect memory performance in rats

Status epilepticus results in region-specific alterations in seizure susceptibility along the hippocampal longitudinal axis

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