Limits...
Electrically induced limbic seizures: preliminary findings in a rodent model.

Kowski AB, Holtkamp M - J Exp Neurosci (2015)

Bottom Line: In epilepsy, novel pharmacological and nonpharmacological treatment approaches are commonly assessed in model systems of acute motor and often generalized seizures.Limbic structures play a major role in human intractable epilepsy.This model may represent a reliable screening tool for new treatment approaches such as deep brain stimulation.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Epilepsy-Center Berlin-Brandenburg, Charité-Universitätsmedizin Berlin, Berlin, Germany.

ABSTRACT
In epilepsy, novel pharmacological and nonpharmacological treatment approaches are commonly assessed in model systems of acute motor and often generalized seizures. We developed a rodent model with short-term electrical stimulation of the perforant path resulting in stereotyped limbic seizures. Limbic structures play a major role in human intractable epilepsy. In 10 rats, single electrical 5-second and 20-Hz stimuli to the perforant path reliably produced limbic seizures characterized by resting behavior and subtle motor signs. Electrophysiological recordings from the dentate gyrus demonstrated a seizure pattern with 4-Hz to 5-Hz discharges. Multiple inductions of seizures within 72 hours did not alter behavioral and electrophysiological seizure characteristics. Electrophysiological excitatory and inhibitory parameters assessed by evoked single and paired pulses did not change with increasing number of seizures. We present preliminary findings on a new model of electrically induced limbic seizures of mesiotemporal origin. This model may represent a reliable screening tool for new treatment approaches such as deep brain stimulation.

No MeSH data available.


Related in: MedlinePlus

Maintained inhibition.Notes: Representative trace of excitatory postsynaptic potentials (EPSP) with superimposed population spike (PS) in the dentate gyrus following paired pulses with an interpulse interval of 25 ms (stimuli artifacts—arrowheads). While the second stimulus still evokes an EPSP, the superimposed PS is completely inhibited. This strong effect remains unchanged even after several seizures. In contrast, at an interpulse interval of 100 ms, the PS following the second stimulus is as large as the one following the first stimulus or even facilitated throughout different stages of the experiment.
© Copyright Policy - open-access
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4376203&req=5

f3-jen-9-2015-007: Maintained inhibition.Notes: Representative trace of excitatory postsynaptic potentials (EPSP) with superimposed population spike (PS) in the dentate gyrus following paired pulses with an interpulse interval of 25 ms (stimuli artifacts—arrowheads). While the second stimulus still evokes an EPSP, the superimposed PS is completely inhibited. This strong effect remains unchanged even after several seizures. In contrast, at an interpulse interval of 100 ms, the PS following the second stimulus is as large as the one following the first stimulus or even facilitated throughout different stages of the experiment.

Mentions: The extent of excitation and inhibition in the dentate gyrus was assessed electrophysiologically by using the paired pulse paradigm as described previously.7 In brief, two identical bipolar pulses of 150-μs duration were applied to the perforant path at interpulse intervals (IPIs) of 20, 25, and 100 ms, respectively. PS latency, PS amplitude, slope of the excitatory postsynaptic potential (EPSP), and paired pulse ratio (PPR) were assessed at predefined time points 10 minutes before induction of some of the seizures (Fig. 1). Latency was defined as time from the first stimulus artifact to the negative PS peak, amplitude as the mean of the descending and ascending parts of the first PS, and slope as the gradient of the inclining part of the first EPSP (Fig. 2). For determining the PPR, the amplitude of the PS following the second stimulus was related to the PS amplitude following the first stimulus (Fig. 3); PPR <1 indicates inhibition of the second PS and PPR >1, facilitation.


Electrically induced limbic seizures: preliminary findings in a rodent model.

Kowski AB, Holtkamp M - J Exp Neurosci (2015)

Maintained inhibition.Notes: Representative trace of excitatory postsynaptic potentials (EPSP) with superimposed population spike (PS) in the dentate gyrus following paired pulses with an interpulse interval of 25 ms (stimuli artifacts—arrowheads). While the second stimulus still evokes an EPSP, the superimposed PS is completely inhibited. This strong effect remains unchanged even after several seizures. In contrast, at an interpulse interval of 100 ms, the PS following the second stimulus is as large as the one following the first stimulus or even facilitated throughout different stages of the experiment.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4376203&req=5

f3-jen-9-2015-007: Maintained inhibition.Notes: Representative trace of excitatory postsynaptic potentials (EPSP) with superimposed population spike (PS) in the dentate gyrus following paired pulses with an interpulse interval of 25 ms (stimuli artifacts—arrowheads). While the second stimulus still evokes an EPSP, the superimposed PS is completely inhibited. This strong effect remains unchanged even after several seizures. In contrast, at an interpulse interval of 100 ms, the PS following the second stimulus is as large as the one following the first stimulus or even facilitated throughout different stages of the experiment.
Mentions: The extent of excitation and inhibition in the dentate gyrus was assessed electrophysiologically by using the paired pulse paradigm as described previously.7 In brief, two identical bipolar pulses of 150-μs duration were applied to the perforant path at interpulse intervals (IPIs) of 20, 25, and 100 ms, respectively. PS latency, PS amplitude, slope of the excitatory postsynaptic potential (EPSP), and paired pulse ratio (PPR) were assessed at predefined time points 10 minutes before induction of some of the seizures (Fig. 1). Latency was defined as time from the first stimulus artifact to the negative PS peak, amplitude as the mean of the descending and ascending parts of the first PS, and slope as the gradient of the inclining part of the first EPSP (Fig. 2). For determining the PPR, the amplitude of the PS following the second stimulus was related to the PS amplitude following the first stimulus (Fig. 3); PPR <1 indicates inhibition of the second PS and PPR >1, facilitation.

Bottom Line: In epilepsy, novel pharmacological and nonpharmacological treatment approaches are commonly assessed in model systems of acute motor and often generalized seizures.Limbic structures play a major role in human intractable epilepsy.This model may represent a reliable screening tool for new treatment approaches such as deep brain stimulation.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Epilepsy-Center Berlin-Brandenburg, Charité-Universitätsmedizin Berlin, Berlin, Germany.

ABSTRACT
In epilepsy, novel pharmacological and nonpharmacological treatment approaches are commonly assessed in model systems of acute motor and often generalized seizures. We developed a rodent model with short-term electrical stimulation of the perforant path resulting in stereotyped limbic seizures. Limbic structures play a major role in human intractable epilepsy. In 10 rats, single electrical 5-second and 20-Hz stimuli to the perforant path reliably produced limbic seizures characterized by resting behavior and subtle motor signs. Electrophysiological recordings from the dentate gyrus demonstrated a seizure pattern with 4-Hz to 5-Hz discharges. Multiple inductions of seizures within 72 hours did not alter behavioral and electrophysiological seizure characteristics. Electrophysiological excitatory and inhibitory parameters assessed by evoked single and paired pulses did not change with increasing number of seizures. We present preliminary findings on a new model of electrically induced limbic seizures of mesiotemporal origin. This model may represent a reliable screening tool for new treatment approaches such as deep brain stimulation.

No MeSH data available.


Related in: MedlinePlus