Cerebral anoxia and disability

p38 MAPK Endogenous Inhibition Improves Neurological Deficits in Global Cerebral Ischemia/Reperfusion Mice

Cerebral ischemia/reperfusion (I/R) injury is a complex pathophysiological process that can lead to neurological function damage and the formation of cerebral infarction. The p38 MAPK pathway has attracted considerable attention in cerebral I/R injury (IRI), but little research has been carried out on its direct role in vivo. In this study, to observe the effects of p38 MAPK endogenous inhibition on cerebral IRI, p38 heterozygous knockdown (p38KI/+) mice were used. We hypothesized that p38 signaling might be involved in I/R injury and neurological damage reduction and that neurological behavioral deficits improve when p38 MAPK is inhibited. First, we examined the neurological damage and neurological behavioral deficit effects of I/R injury in WT mice. Cerebral I/R injury was induced by the bilateral common carotid artery occlusion (BCCAO) method. The cerebral infarction area and volume were assessed and analyzed by 2,3,5-triphenyltetrazolium chloride (TTC) staining. p38 MAPK and caspase-3 were detected by western blotting. Neuronal apoptosis was measured using TUNEL staining. Neurological deficits were detected by behavioral testing. Furthermore, to assess whether these neuroprotective effects occurred when p38 MAPK was inhibited, p38 heterozygous knockdown (p38KI/+) mice were used. We found that p38 MAPK endogenous inhibition rescued hippocampal cell apoptosis, reduced ischemic penumbra, and improved neurological behavioral deficits. These findings showed that p38 MAPK endogenous inhibition had a neuroprotective effect on IRI and that p38 MAPK may be a potential therapeutic target for cerebral IRI.

The influence of cognitive reserve in the protection of the cognitive status after an acquired brain injury: A systematic review

BACKGROUND

Cognitive Reserve (CR) hypothesis was introduced to account for the variability in cognitive performance of patients with similar degrees of brain injury or pathology. The individual variability of CR is modulated by the interaction of innate capacities and exposures throughout life, which can act as protectors against neuropathology's clinical effects. Individuals with higher CR appear to have better cognitive performance after a brain injury. The present review aimed to identify and map the scientific evidence available in literature regarding CR's influence in protecting the cognitive status after an Acquired Brain Injury (ABI).

METHOD

A systematic review was performed for published studies until October 2020 in PubMed, Scopus, and CINAHL electronic databases. Studies regarding CR's influence in protecting the cognitive status after an ABI were included in this review. The Newcastle-Ottawa Scale was used to assess risk of bias in the included studies. This systematic review was recorded in the International Prospective Register of Systematic Reviews (PROSPERO) under the number CRD42021236594.

RESULTS

Twenty-one studies published between 2003 and 2020 were selected and analyzed. The literature analysis showed that CR has a positive effect on cognitive status after an ABI. Various proxies were used to estimate CR, including estimated premorbid IQ, education, occupation attainment, socioeconomic status, leisure activities, bilingualism, and social integration. CR proxies constitute a set of variables that may have a significant influence on cognitive status. Higher CR levels were associated with lower cognitive impairment after an ABI.

CONCLUSIONS

Although more research is necessary for a complete understanding of CR's impact on cognition, the synthesis of these studies confirmed that there is evidence on the beneficial impact of CR on cognitive status after an ABI. These findings support CR's cognitive status role following an ABI and may provide additional information for prognosis and rehabilitation plans.

Effect of Acute Normobaric Hypoxia Exposure on Executive Functions among Young Physically Active Males

Background: On the one hand, hypoxic exposure may result in progressive brain metabolism disturbance, causing subsequent cognitive impairments. On the other hand, it might also enhance neurogenesis and brain vascularization as well as accelerate cerebral blood flow, leading to cognitive function improvement. The aim of this study was to investigate whether progressive stages of normobaric hypoxia (NH) (FIO₂ = 13%, FIO₂ = 12%, and FIO₂ = 11%) differentially affect post-exposure cognitive performance. Methods: Fifteen physically active men (age = 23.1 ± 2.1) participated in the study. The Stroop test (ST) was applied to assess cognitive function. To generate NH conditions, a hypoxic normobaric air generator was used. Results: We observed an executive function impairment (“naming” interference p < 0.05) after NH exposure (FIO₂ = 13%). After exposure at FIO₂ = 12% and FIO₂ = 11%, no changes were observed in the Stroop test. Also, changes in SpO₂ during subsequent NH exposure were observed. Conclusions: The current investigation shows that executive functions deteriorate after acute NH exposure and this post-exposure deterioration is not proportional to the normobaric hypoxia stages among young physically active males.

Communicative and swallowing disorders in anoxic patients: A retrospective study on clinical outcomes and performance measures

BACKGROUND

Anoxic brain injury (ABI) is a neurological condition associated to a severe deterioration of brain functioning, whose symptomatology and clinical outcomes may be heterogeneous: cognitive deficits, language disorders like dysarthria and swallowing impairments. Nevertheless, there is still a lack of information on the rehabilitation outcomes.

OBJECTIVE

To confirm the occurrence of communication and swallowing deficits in 37 ABI patients and to examine whether intensive rehabilitation may contribute to any improvements and its relation to ABI severity and functional autonomy.

METHODS

37 patients, hospitalized at IRCCS San Camillo Hospital from 2011 to 2018 were analyzed retrospectively. All patients completed a functional evaluation and a language and swallowing assessment, within one week from hospital admission (T0). The assessment was repeated after an intensive rehabilitation treatment (T1).

RESULTS

Results show that dysphagia is a frequent and severe outcome in anoxic patients, whereas communication disorders (aphasia and dysarthria) are less severe. Moreover, ABI patients seem to be positively sensitive to an intensive rehabilitation program.

CONCLUSIONS

An early multidisciplinary management of communicative-linguistic and swallowing functions is crucial in order to prevent adverse events and to plan a tailored rehabilitation pathway.

Daily FOUR score assessment provides accurate prognosis of long-term outcome in out-of-hospital cardiac arrest

BACKGROUND

The accurate prediction of outcome after out-of-hospital cardiac arrest (OHCA) is of major importance. The recently described Full Outline of UnResponsiveness (FOUR) is well adapted to mechanically ventilated patients and does not depend on verbal response.

OBJECTIVE

To evaluate the ability of FOUR assessed by intensivists to accurately predict outcome in OHCA.

METHODS

We prospectively identified patients admitted for OHCA with a Glasgow Coma Scale below 8. Neurological assessment was performed daily. Outcome was evaluated at 6 months using Glasgow-Pittsburgh Cerebral Performance Categories (GP-CPC).

RESULTS

Eighty-five patients were included. At 6 months, 19 patients (22%) had a favorable outcome, GP-CPC 1-2, and 66 (78%) had an unfavorable outcome, GP-CPC 3-5. Compared to both brainstem responses at day 3 and evolution of Glasgow Coma Scale, evolution of FOUR score over the three first days was able to predict unfavorable outcome more precisely. Thus, absence of improvement or worsening from day 1 to day 3 of FOUR had 0.88 (0.79-0.97) specificity, 0.71 (0.66-0.76) sensitivity, 0.94 (0.84-1.00) PPV and 0.54 (0.49-0.59) NPV to predict unfavorable outcome. Similarly, the brainstem response of FOUR score at 0 evaluated at day 3 had 0.94 (0.89-0.99) specificity, 0.60 (0.50-0.70) sensitivity, 0.96 (0.92-1.00) PPV and 0.47 (0.37-0.57) NPV to predict unfavorable outcome.

CONCLUSION

The absence of improvement or worsening from day 1 to day 3 of FOUR evaluated by intensivists provides an accurate prognosis of poor neurological outcome in OHCA.

Anxiety related to discharge from inpatient neurorehabilitation: Exploring the role of self-efficacy and internal health control beliefs

The study aimed to determine the prevalence of anxiety related to discharge, among a group of 42 participants who were likely to have sustained an at least moderate to severe ABI and who were due to be discharged home following a period of inpatient neurorehabilitation. Differential relationships between psychological factors (self-efficacy and internal health control beliefs) were examined, alongside the relative influence of demographic and clinical characteristics on discharge anxiety. Data were obtained via self-report measures and retrospective reviews of participant's inpatient medical records. While relatively few participants (n = 6; 14%) reported markedly elevated trait-anxiety, almost half the sample (n = 19; 45%) reported clinically significant levels of transient state-anxiety. Notably, state-anxiety was strongly associated with discharge anxiety. Multivariate analyses revealed that age, self-efficacy and internal health control beliefs made independent contributions to self-reported discharge anxiety, with perceived self-efficacy alone explaining 69% of the variance and mediating the effects of age and internal health control beliefs. None of the other demographic or clinical characteristics examined was significantly associated with discharge anxiety. While causality cannot be inferred, findings suggest that anxiety related to discharge from rehabilitation might be best predicted by poor perceptions of self-efficacy. Implications for clinical practice and future research are discussed.

Genetic Deletion of Prostacyclin IP Receptor Exacerbates Transient Global Cerebral Ischemia in Aging Mice

Transient global cerebral ischemia causes delayed neuronal death in the hippocampal CA1 region. It also induces an up regulation of cyclooxygenase 2 (COX-2), which generates several metabolites of arachidonic acid, known as prostanoids, including Prostaglandin I2 (PGI2). The present study investigated whether the PGI2 IP receptor plays an important role in brain injury after global cerebral ischemia in aged mice. Adult young (2-3 months) and aged (12-15 months) male C57Bl/6 wild-type (WT) or IP receptor knockout (IP KO) mice underwent a 12 min bilateral common carotid artery occlusion (BCCAO) or a sham surgery. Behavior tests (neurologic deficit and T-maze) were performed 3 and 7 days after BCCAO. After seven days of reperfusion, the numbers of cells positive for markers of neurons, astrocytes, microglia, myeloperoxidase (MPO) and phosphorylated CREB (p-CREB) were evaluated immunohistochemically. Interestingly, in young and aged IP KO ischemic mice, there was a significant increase (p < 0.01) in cognitive deficit, hippocampal CA1 pyramidal neuron death, microglia and MPO activation, while p-CREB was reduced as compared to their corresponding WT controls. These data suggest that following ischemia, IP receptor deletion contributes to memory and cognitive deficits regulated by the CREB pathway and that treatment with IP receptor agonists could be a useful target to prevent harmful consequences.

Fish oil provides robust and sustained memory recovery after cerebral ischemia: influence of treatment regimen

We previously reported that long-term treatment with fish oil (FO) facilitates memory recovery after transient, global cerebral ischemia (TGCI), despite the presence of severe hippocampal damage. The present study tested whether this antiamnesic effect resulted from an action of FO on behavioral performance itself, or whether it resulted from an anti-ischemic action. Different treatment regimens were used that were distinguished from each other by their initiation or duration with regard to the onset of TGCI and memory assessment. Naive rats were trained in an eight-arm radial maze, subjected to TGCI (4-VO model, 15 min), and tested for memory performance up to 6 weeks after TGCI. Fish oil (docosahexaenoic acid, 300 mg/kg/day) was given orally according to one of the following regimens: regimen 1 (from 3 days prior to ischemia until 4 weeks post-ischemia), regimen 2 (from 3 days prior to ischemia until 1 week post-ischemia), and regimen 3 (from week 2 to week 5 post-ischemia). When administered according to regimens 1 and 2, FO abolished amnesia completely. This effect persisted for at least 5 weeks after discontinuing the treatment. Such an effect did not occur, however, in the group treated according to regimen 3. Hippocampal and cortical damage was not alleviated by FO. The present results demonstrate that FO-mediated memory recovery (or preservation) following TGCI is a reproducible, robust, and long-lasting effect. Moreover, such an effect was found with a relatively short period of treatment, provided it covered the first days prior to and after ischemia. This suggests that FO prevented amnesia by changing some acute, ischemia/reperfusion-triggered process and not by stimulating memory performance on its own.

Response of hippocampal neurons and glial cells to alternating magnetic field in gerbils submitted to global cerebral ischemia

The purpose of this study was to determine whether exposure to an extremely low-frequency magnetic field (ELF-MF, 50 Hz) affects the outcome of postischemic damage in the hippocampus of Mongolian gerbils. After 10-min bilateral carotid occlusion, the gerbils were continuously exposed to ELF-MF (average magnetic induction at the center of the cage was 0.5 mT) for 7 days. The impact of ELF-MF was estimated immediately (the 7th day after reperfusion) and 7 days after cessation of exposure (the 14th day after reperfusion) compared with ischemic gerbils without ELF-MF exposure. Applying stereological methods, histological evaluation of changes in the hippocampus was done for determining its volume, volume densities of degenerating neurons and astrocytes, as well as the number of microglial cells per unit area. ELF-MF per se did not induce any morphological changes, while 10-min global cerebral ischemia led to neuronal death, especially in CA1 region of the hippocampus, as expected. Ischemic gerbils exposed to ELF-MF had significantly a lower degree of cell loss in the examined structure and greater responses of astrocytes and microglial cells than postischemic gerbils without exposure on the seventh day after reperfusion (immediate effect of ELF-MF). Similar response was observed on the 14th day after reperfusion (delayed effect of ELF-MF); however, differences in measured parameters were low and insignificant. Applied ELF-MF has possible neuroprotective function in the hippocampus, as the most sensitive brain structure in the model of global cerebral ischemia, through reduction of neuronal death and activation of astrocytes and microglial cells.

Neuroprotective effects of Eleutherococcus senticosus bark on transient global cerebral ischemia in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Eleutherococcus senticosus Maxim., classified into the family of Araliaceae, is used in a variety of diseases in traditional Korean medicine including ischemic heart disease.

AIM OF THE STUDY

To determine the neuroprotective effects of Eleutherococcus senticosus on global cerebral ischemia.

MATERIALS AND METHODS

A four-vessel occlusion (4-VO) rat model was used to evaluate the potential protective effects against transient global cerebral ischemia ethanol extracts of Eleutherococcus senticosus was orally administered at doses of 3, 30, and 300 mg/kg twice at times of 0 and 90 min after reperfusion. The effects on memory deficit were investigated by using a Y-maze neurobehavioral test after brain ischemia, and the effects on hippocampal neuronal damage were measured 7 days after ischemia. The expressions of glial fibrillary acid protein (GFAP), CD11b antibody (OX-42), and cyclooxygenase-2 (COX-2) were investigated by immunohistochemistry.

RESULTS

Oral administration of Eleutherococcus seticosus at 30, 100 and 300 mg/kg significantly reduced hippocampal CA1 neuronal death by 3.5%, 25.9% and 53.1%, respectively, compared with a vehicle-treated group. Oral administration of Eleutherococcus senticosus at 300 mg/kg inhibited 81.9% of the decrease in spontaneous alternation induced by 4-VOin the Y-maze test, and also attenuated ischemia-induced activation of COX-2, GFAP and OX-42 in the hippocampal CA1 region.

CONCLUSION

Eleutherococcus senticosus protects delayed neuronal death in the CA1 region of the hippocampus against global cerebral ischemia in rats with the recovery of spatial memory, which can be considered as the normal functioning of the hippocampus. Regarding the immunohistochemical study, the effect of Eleutherococcus senticosus may be attributable to its anti-inflammatory properties through the inhibition of COX-2 expression, microglia and astrocyte expression.

Extremely low frequency magnetic field induced changes in motor behaviour of gerbils submitted to global cerebral ischemia

The purpose of this study was to evaluate behavioural effects of an extremely low frequency magnetic field (ELF-MF) in 3-month-old Mongolian gerbils submitted to global cerebral ischemia. After 10-min occlusion of both common carotid arteries, the gerbils were placed in the vicinity of an electromagnet and continuously exposed to ELF-MF (50Hz, 0.5mT) for 7 days. Their behaviour (locomotion, stereotypy, rotations, and immobility) was monitored on days 1, 2, 4, 7, and 14 after reperfusion for 60min in the open field. It was shown that the 10-min global cerebral ischemia per se induced a significant motor activity increase (locomotion, stereotypy and rotations), and consequently immobility decrease until day 4 after reperfusion, compared to control gerbils. Exposure to ELF-MF inhibited development of ischemia-induced motor hyperactivity during the whole period of registration, but significantly in the first 2 days after reperfusion, when the postischemic hyperactivity was most evident. Motor activity of these gerbils was still significantly increased compared to control ones, but only on day 1 after reperfusion. Our results revealed that the applied ELF-MF (50Hz, 0.5mT) decreased motor hyperactivity induced by the 10-min global cerebral ischemia, via modulation of the processes that underlie this behavioural response.

Cognitive dysfunction and health-related quality of life after a cardiac arrest and therapeutic hypothermia

BACKGROUND

Evidence-based treatment protocols including therapeutic hypothermia have increased hospital survival to over 50% in unconscious out-of-hospital cardiac arrest survivors. In this study we estimated the incidence of cognitive dysfunctions in a group of cardiac arrest survivors with a high functional outcome treated with therapeutic hypothermia. Secondarily, we assessed the cardiac arrest group's level of cognitive performance in each tested cognitive domain and investigated the relationship between cognitive function and age, time since cardiac arrest and health-related quality of life (HRQOL).

METHODS

We included 26 patients 13-28 months after a cardiac arrest. All patients were scored using the Cerebral Performance Category scale (CPC) and Mini-Mental State Examination (MMSE). Twenty-five of the patients were tested for cognitive function using the Cambridge Neuropsychological Test Automated Battery (CANTAB). These patients were tested using four cognitive tests: Motor Screening Test, Delayed Matching to Sample, Stockings of Cambridge and Paired Associate Learning from CANTAB. All patients filled in the Short Form-36 for the assessment of HRQOL.

RESULTS

Thirteen of 25 (52%) patients were classified as having a cognitive dysfunction. Compared with the reference population, there was no difference in the performance in motor function and delayed memory but there were significant differences in executive function and episodic memory. We found no associations between cognitive function and age, time since cardiac arrest or HRQOL.

CONCLUSION

Half of the patients had a cognitive dysfunction with reduced performance on executive function and episodic memory, indicating frontal and temporal lobe affection, respectively. Reduced performance did not affect HRQOL.

Hypoxisch-ischämische Enzephalopathie (HIE) nach Herz-Kreislaufstillstand (HKS) – Pathophysiologie, Prognose und Outcome eines „vernachlässigten“ Krankheitsbildes

Durch die Fortschritte in der Reanimations- und Intensivmedizin steigt die Anzahl von Patienten mit einer Hypoxisch-ischämischen Enzephalopathie (HIE). Das klinische Ausprägungsspektrum dieses Krankheitsbildes reicht von milden kognitiven Dysfunktionen bis hin zum Versterben des Patienten. Der Übersichtsartikel beleuchtet mögliche Entwicklungsverläufe dieser Patientenpopulation vom Akutstadium der Erkrankung bis in die postrehabilitative Phase unter besonderer Gewichtung der zu Grunde liegenden pathophysiologischen Mechanismen, der Prognosestellung sowie des neuropsychologischen und psychosozialen Outcomes. Dabei wird verdeutlicht, dass Verbesserungen in der akuten Rettungs- und Intensivmedizin gleichsam mit Verbesserungen des rehabilitativen und vor allem des postrehabilitativen Versorgungssystems einhergehen müssen – sowohl für Patienten als auch deren Angehörigen.

Neuropsychological profile of persons with anoxic brain injury: Differences regarding physiopathological mechanism

PRIMARY OBJECTIVE

To determine the neuropsychological profile of persons with anoxic brain injury.

METHODS AND PROCEDURES

A retrospective study on a population of persons with anoxic brain injury admitted to a Brain Injury Unit (Institut Guttmann, Spain) from 1995-2003. The sample was divided according to physiopathological mechanisms in two sub-groups: ischemic anoxia (21 cases) and hypoxemic anoxia (11 cases). Functions assessed included orientation, attention, language, visuo-perceptive and visuo-constructive processing and verbal memory.

RESULTS

Neuropsychological assessment showed diffuse cognitive impairment in all assessed functions. Episodes of ischemic anoxia caused more severe verbal memory and learning problems than episodes of hypoxemic anoxia.

CONCLUSIONS

This study shows that memory problems are the most prominent and relevant impairment, although all other cognitive functions are also impaired, affecting both memory itself and general behaviour. Statistical analysis also provides preliminary evidence on the different profile of memory impairment whether cerebral anoxia had hypoxic or ischemic origin.

Cognitive impairments in survivors of out-of-hospital cardiac arrest: a systematic review

OBJECTIVE

To describe the current evidence on the frequency and nature of cognitive impairments in survivors of out-of-hospital cardiac arrest.

DESIGN

Systematic review.

DATA SOURCES

Pubmed, Embase, PsychInfo and Cinahl (1980-2006). No language restriction was imposed.

REVIEW METHODS

The following inclusion criteria were used: participants had to be survivors of out-of-hospital cardiac arrest, 18 years or older, and there had to be least one cognitive outcome measure with a follow-up of 3 months or more. Case reports and qualitative studies were excluded. The articles were screened on title, abstract and full text by two reviewers. All selected articles were reviewed and assessed by two reviewers independently using a quality criteria list.

RESULTS

Out of the 286 articles initially identified, 28 were selected for final evaluation. There was a high heterogeneity between the studies with regard to study design, number of participants, outcome measures and duration of follow-up. In general, the quality of the articles appeared low, with a few positive exceptions. The reported frequency of cognitive impairments in survivors of out-of-hospital cardiac arrest ranged from 6% to 100%. Memory problems were the most common cognitive impairment, followed by impairments in attention and executive functioning. Three high-quality prospective studies found that cognitive problems occurred in about half of the survivors of out-of-hospital cardiac arrest.

CONCLUSION

There are few good studies on the frequency of cognitive impairments after out-of-hospital cardiac arrest. However, cognitive problems, in particular memory problems, seem common in survivors of out-of-hospital cardiac arrest.

[Fantastic confabulations or delusion?]

INTRODUCTION

Confabulations are inaccurate narratives purporting to convey information about the world or the self. Fantastic utterances from brain-injured patients are difficult to interpret as confabulation or delusion.

METHODS

Starting from two clinical observations, we analyse the terms "spontaneous confabulations" and "delusion".

RESULTS

Two brain-injured patients presented with fantastic utterances; the adhesion was complete for both patients. They also suffered from amnesic and executive disorders. Clinical interviews with neuropsychologist and psychopathologist could not distinct between spontaneaous confabulations and delusion.

DISCUSSION

Neuropsychological interpretations of spontaneous confabulations are (1) the deficient strategic retrieval process arising from executive failures and (2) confusion of the temporal order of information within memory. These hypotheses cannot explain the fantastic utterances described. Are spontaneous fantastic confabulations a specific entity or did these patients present a morbid association of neurological and psychiatric disorders? Fantastic confabulations are very scarcely described and the association of neurological and psychiatric impairments enables us to better describe the clinical observations. Spontaneous confabulations reported after amnesic and executive disorders are indeed typically composed of the patient's past experiences and do not usually comprehend fantastic utterances.

CONCLUSION

Neurological and psychological analyses of the fantastic utterances from two brain-injured patients do not respond to the definition of spontaneous confabulation. Fantastic confabulations are a rare entity and we propose another explanation consisting of the association of neurological and psychiatric disorders.

Long-lasting cognitive injury in rats with apparent full gross neurological recovery after short-term cardiac arrest

OBJECTIVE

The long-term behavioral effects of mild global ischemia have not been well described. We used short (5 min) asphyxic-cardiac arrest that resulted in no apparent gross neurological deficits to study the long-term effects of mild hypoxic ischemia on the neurobehavioral status of rats.

METHODS

Fifteen adult, male Wistar rats were studied. One group was given asphyxic-cardiac arrest (CA) for 5 min (n=10) and the other group had Sham procedure (n=5). Neurobehavioral testing was performed before and 2 weeks after CA. The neurobehavioral evaluations were: neurological deficit score (NDS), Y Maze, open field, pre-pulse inhibition (PPI) of acoustic startle reflex (ASR), wire hanging, and inclined screen.

RESULTS

At 24h post-CA, all of the rats regained normal neurological function as measured by NDS, an integral score for consciousness, brainstem reflexes, sensorimotor function and simple behavioral reflex tests. However, 1 week after CA, the rats exhibited significant activity reductions in the open field and in spontaneous alternation in the Y maze. The CA rats also showed a significant decrease in startle reaction amplitude and startle inhibition in the PPI tests. Two weeks after CA, the changes in motor activity and deficits in PPI remained significant, but the spontaneous alternation recovered. The muscle strength test of wire hanging and inclined screen tests did not exhibit significant change.

CONCLUSION

We present a rodent model of mild CA that, despite apparent full recovery of global neurological function at 24h post-resuscitation, exhibited long-term cognitive injury lasting for at least 2 weeks after CA. This model may help understand better the injury associated with CA and develop management strategies for mild brain injury.

NMDA receptor-mediated excitotoxicity contributes to the cerebral hypoxic injury of a rat model of posthypoxic myoclonus

Cardiac arrest-induced cerebral hypoxic injury could induce posthypoxic movement disorders. Here we investigated the effects of memantine, an NMDA receptor channel blocker, on the neurodegeneration occurred in an established rat model of posthypoxic myoclonus. We found that administration of memantine for 7 days significantly reduced cerebral hypoxia-induced neurodegeneration in the CA1 of the hippocampus, the reticular thalamic nucleus (RTN) and the primary fissure of the cerebellum of the posthypoxic animals. The results suggest that the neurodegeneration observed in specific areas of the brain of the posthypoxic rats is contributed by NMDA receptor-mediated excitotoxicity.