Long-term enhancement of entorhinal-dentate evoked potentials following 'modified' ECS in the rat

Electroconvulsive therapy for super refractory status epilepticus in pregnancy: case report and review of literature

OBJECTIVE

We aim to describe use of electroconvulsive therapy (ECT) to treat super refractory status epilepticus (SRSE) in pregnancy and review the literature regarding utility and safety of ECT in refractory status epilepticus.

BACKGROUND

Status epilepticus (SE) is a commonly encountered emergency in neuro-critical care world. Pharmacotherapy of status epilepticus in pregnancy is very challenging given the effect of the majority of antiepileptic drugs (AEDs) on fetal development. Although there has been growing evidence for use of ECT in status epilepticus, data about its utility in pregnancy is lacking.

DESIGN/METHOD

A twenty-one year old Caucasian female with history of epilepsy presented at 8 weeks of gestation as status epilepticus (SE) after abrupt discontinuation of her AEDs. Treatment was initiated with standard regimen of benzodiazepine and levetiracetam, which was progressively expanded to include approximately 10 anti-epileptic drugs over the course of 30 days. The status epilepticus was super refractory to sedation. She underwent ECT on day 31 with remarkable improvement in electroencephalogram (EEG) pattern and resolution of status epilepticus following a single ECT session. We reviewed PubMed and collated case reports involving the use of ECT in status epilepticus with emphasis on differences in various confounding factors esp. etiology of status and age group.

CONCLUSION

Our case is the first reported case of ECT for successful treatment of SRSE in pregnancy. While majority AEDs pose a significant maternal and fetal risk during pregnancy, ECT could be a potential frontline therapy for SE in pregnancy.

Sustained Ultrastructural Changes in Rat Hippocampal Formation After Repeated Electroconvulsive Seizures

BACKGROUND

Electroconvulsive therapy (ECT) is a highly effective and fast-acting treatment for depression used in the clinic. Its mechanism of therapeutic action remains uncertain. Previous studies have focused on documenting neuroplasticity in the early phase following electroconvulsive seizures (ECS), an animal model of ECT. Here, we investigate whether changes in synaptic plasticity and nonneuronal plasticity (vascular and mitochondria) are sustained 3 months after repeated ECS trials.

METHODS

ECS or sham treatment was given daily for 1 day or 10 days to a genetic animal model of depression: the Flinders Sensitive and Resistant Line rats. Stereological principles were employed to quantify numbers of synapses and mitochondria as well as length of microvessels in the hippocampus 24 hours after a single ECS. Three months after 10 ECS treatments (1 per day for 10 days) and sham-treatment, brain-derived neurotrophic factor and vascular endothelial growth factor protein levels were quantified with immunohistochemistry.

RESULTS

A single ECS treatment significantly increased the volume of hippocampal CA1-stratum radiatum, the total length of microvessels, mitochondria number, and synapse number. Observed changes were sustained as shown in the multiple ECS treatment group analyzed 3 months after the last of 10 ECS treatments.

CONCLUSION

A single ECS caused rapid effects of synaptic plasticity and nonneuronal plasticity, while repeated ECS induced long-lasting changes in the efficacy of synaptic plasticity and nonneuronal plasticity at least up to 3 months after ECS.

Electroconvulsive Shock Induces Neuron Death in the Mouse Hippocampus: Correlation of Neurodegeneration with Convulsive Activity

The relationship between convulsive activity evoked by repeated electric shocks and structural changes in the hippocampus of Balb/C mice was studied. Brains were fixed two and seven days after the completion of electric shocks, and sections were stained by the Nissl method and immunohistochemically for apoptotic nuclei (the TUNEL method). In addition, the activity of caspase-3, the key enzyme of apoptosis, was measured in brain areas immediately after completion of electric shocks. The number of neurons decreased significantly in field CA1 and the dentate fascia, but not in hippocampal field CA3. The numbers of cells in CA1 and CA3 were inversely correlated with the intensity of convulsions. Signs of apoptotic neuron death were not seen, while caspase-3 activity was significantly decreased in the hippocampus after electric shocks. These data support the notion that functional changes affect neurons after electric shock and deepen our understanding of this view, providing direct evidence that there are moderate (up to 10%) but significant levels of neuron death in defined areas of the hippocampus. Inverse correlations of the numbers of cells with the extent of convulsive activity suggest that the main cause of neuron death is convulsions evoked by electric shocks.

Spikes immediately after electroconvulsive therapy in psychotic patients

The goal of this study was to assess the spikes systematically and to clarify an epileptc abnormality induced by electroconvulsive therapy (ECT). Our subjects were 20 psychotic patients with no spikes on prior EEGs. ECT was performed by applying electrical current to both sides of the patient's temple every 2 or 3 days for a period of between 1-4 weeks. The first EEG examination was performed either on the day that the ECT course was completed or on the following day. Subsequent EEG examinations were performed at intervals of 2 or 3 days. Thirteen of the 20 patients showed spikes. There were no significant differences in age, gender, diagnosis, or type of ECT. Patients with spikes had significantly more ECT sessions than those without spikes. The spikes were present in the frontal, temporal and central areas, predominantly frontal, anterior temporal and mid-temporal region, and almost disappeared in 1-3 weeks. The occurrence of spikes immediately after ECT was demonstrated. Although this abnormality was transient, it could indicate that in humans ECT causes the early stage of kindling phenomenon as a result of repeated application, and that the temporal lobe seems to play a major role in order to induce the phenomenon.

Electroshocks delay seizures and subsequent epileptogenesis but do not prevent neuronal damage in the lithium-pilocarpine model of epilepsy

Electroconvulsive therapy, which is used to treat refractory major depression in humans increases seizure threshold and decreases seizure duration. Moreover, the expression of brain derived neurotrophic factor induced by electroshocks (ECS) might protect hippocampal cells from death in patients suffering from depression. As temporal lobe epilepsy is linked to neuronal damage in the hippocampus, we tested the effect of repeated ECS on subsequent status epilepticus (SE) induced by lithium-pilocarpine and leading to cell death and temporal epilepsy in the rat. Eleven maximal ECS were applied via ear-clips to adult rats. The last one was applied 2 days before the induction of SE by lithium-pilocarpine. The rats were electroencephalographically recorded to study the SE characteristics. The rats treated with ECS before pilocarpine (ECS-pilo) developed partial limbic (score 2) and propagated seizures (score 5) with a longer latency than the rats that underwent SE alone (sham-pilo). Despite this delay in the initiation and propagation of the seizures, the same number of ECS- and sham-pilo rats developed SE with a similar characteristic pattern. The expression of c-Fos protein was down-regulated by repeated ECS in the amygdala and the cortex. In ECS-pilo rats, c-Fos expression was decreased in the piriform and entorhinal cortex and increased in the hilus of the dentate gyrus. Neuronal damage was identical in the forebrain areas of both groups, while it was worsened by ECS treatment in the substantia nigra pars reticulata, entorhinal and perirhinal cortices compared to sham-pilo rats. Finally, while 11 out of the 12 sham-pilo rats developed spontaneous recurrent seizures after a silent period of 40+/-27 days, only two out of the 10 ECS-pilo rats became epileptic, but after a prolonged latency of 106 and 151 days. One ECS-pilo rat developed electrographic infraclinical seizures and seven did not exhibit any seizures. Thus, the extensive neuronal damage occurring in the entorhinal and perirhinal cortices of the ECS-pilo rats seems to prevent the establishment of the hyperexcitable epileptic circuit.

Neurogenesis in the dentate gyrus of the rat following electroconvulsive shock seizures

Electroconvulsive shock (ECS) seizures provide an animal model of electroconvulsive therapy (ECT) in humans. Recent evidence indicates that repeated ECS seizures can induce long-term structural and functional changes in the brain, similar to those found in other seizure models. We have examined the effects of ECS on neurogenesis in the dentate gyrus of the adult rat using bromodeoxyuridine (BrdU) immunohistochemistry, which identifies newly generated cells. Cells have also been labeled for neuronal nuclear protein (NeuN) to identify neurons. One month following eight ECS seizures, ECS-treated rats had approximately twice as many BrdU-positive cells as sham-treated controls. Eighty-eight percent of newly generated cells colabeled with NeuN in ECS-treated subjects, compared to 83% in sham-treated controls. These data suggest that there is a net increase in neurogenesis within the hippocampal dentate gyrus following ECS treatment. Similar increases have been reported following kindling and kainic acid- or pilocarpine-induced status epilepticus. Increased neurogenesis appears to be a general response to seizure activity and may play a role in the therapeutic effects of ECT.

Ketamine and phenobarbital do not reduce the evoked-potential enhancement induced by electroconvulsive shock seizures in the rat

Electroconvulsive shock (ECS) seizures provide an animal analog of electroconvulsive therapy (ECT). Repeated ECS seizures cause a long-lasting, and perhaps permanent, enhancement of entorhinal-dentate evoked potentials (EPs) in the rat. Recently it has been reported that ketamine protects against ECS-induced EP enhancement. The present study was designed to replicate these findings and to extend them by incorporating a phenobarbital group (to control for ketamine's partial diminution of seizures) and an animal test of antidepressant activity (the Porsolt test). Unexpectedly, we found that neither ketamine nor phenobarbital protected against ECS-induced enhancement of EPs. Both, however, diminished the 'therapeutic' effects of ECS, as modeled by the Porsolt test. These data suggest that the use of ketamine would not eliminate the unwanted effects of ECT and that it might diminish ECT's therapeutic benefits.

Amygdala-kindled and electroconvulsive seizures alter hippocampal expression of the m1 and m3 muscarinic cholinergic receptor genes

Expression of m1 and m3 muscarinic cholinergic receptors mRNAs was examined in rat hippocampus following either: (1) kindling to five Stage 5 amygdala-kindled seizures; or (2) eight electroconvulsive shock (ECS) seizures. Twenty-four hours after the last seizure of either type, there was a significant decrease in both m1 and m3 mRNAs in CA1, CA3 and the dentate gyrus subfields of the hippocampus. Twenty-eight days after the last seizure of either type, there was a significant increase in m1 mRNAs in CA1, CA3, and the dentate gyrus; for m3 mRNAs, there was a significant increase in CA3 28 days after the last ECS seizure, and in CA1 and CA3 28 days after the last kindled seizure. These results suggest that seizures alter the cholinergic system in the hippocampus, and that some of the alterations are very long-lasting.