摘要:

Summary:Aberrant synapse formation has been implicated in development and propagation of epileptic potential. Litzinger et al. (1993a) showed that ω‐GVIA conotoxin may be used as a marker for synapse formation in nonepileptic mice. We conducted ω‐GVIA binding in synaptosomal preparations from epileptic DBA/2J mice at different developmental ages. Binding in DBA/2J mice was compared with ω‐GVIA binding in synaptosomal preparations from nonepileptic C57/B1, Swiss Webster, and AJ mice. Striking differences between these strains of mice are evident in the developmental sequence and pattern of N‐type voltage‐sensitive calcium channels (VSCC). In contrast to nonepileptic mice, the DBA/2J mice show a slow increase in ω‐GVIA binding between postnatal days 2 and 8. This increase corresponds to onset of susceptibility to seizure in this strain. In addition to the difference in developmental sequence, DBA/2J mice have fewer binding sites for ω‐GVIA throughout development, suggesting changes in channel structure or number. These data show that in DBAI2J mice development of the VSCC in brain is different from that in nonepileptic mice. This difference in development in presynaptic membranes responsible for neurotransmitter release may represent a change in synaptic activity that plays a role

ISSN:0013-9580    

DOI:10.1111/j.1528-1157.1994.tb02533.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Summary:Spontaneous unit discharges in stratum pyramidale of CA1 area of hippocampal slices from DBA and CS7 mice at different ages were recorded extracellularly. The average rate and amplitude of the spontaneous discharges from CA1 area of hippocampal slices bathed in artificial cerebrospinal fluid (aCSF) were not different between DBA and CS7 mice at either 3–4 or 5–6 weeks of age. Bath application of kainic acid (KA) in concentrations of 0·5–1·0 μM produced different responses in CA1 area from these two strains of mice. In DBA mice at age 3–4 weeks, when they are most susceptible to audiogenic seizures, KA perfusion induced high‐frequency repetitive single spikes and bursts of multiple population spikes in CA1 area. Very high‐frequency discharges (10‐fold higher than most responses) were also observed in 20% of all slices. In audiogenic seizure resistant CS7 mice at age 3–4 weeks, KA perfusion at the same doses induced only the repetitive single spikes. The rate of spontaneous discharges was much lower than that in DBA mice. No burst of multiple population spikes nor very high‐frequency responses were recorded in CS7 mice. At age 5–6 weeks, when both DBA and CS7 mice are resistant to audiogenic seizures, the rate of spontaneous discharges recorded from the CAI area during and after KA perfusion was lower than that at age 3–4 weeks, and there was no significant difference between DBA and CS7 mice. Pretreatment of hippocampal slices with AMPA/kainate receptor antagonist CNQX (10pA4) markedly reduced the rate and amplitude of spontaneous discharges in CA1 area during and after KA perfusion, whereas competitive N‐methyl‐D‐aspartate (NMDA) receptor antagonist D‐APS had no effect. These results indicate that the responses in spontaneous discharges recorded extracellularly from stratum pyramidale in CA1 area of hippocampal slices to KA perfusion correlate with susceptibility to audioge

ISSN:0013-9580    

DOI:10.1111/j.1528-1157.1994.tb02534.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Summary:Free concentration of valproate (VPA) was measured simultaneously and continuously in blood and in the extracellular space of cerebral cortex of rats by VPA‐selective microelectrodes. Constant amounts of VPA were injected into the femoral vein with differing duration of injection. Immediately after drug application, the concentration of free VPA in blood and brain increased to a peak value, the degree of which increased with the speed of injection. Ten to 15 min after VPA injection, a plateau value was reached. This plateau value was equal in the extracellular space of cortex and in blood. The data indicate that VPA can “freely” cross the blood‐brain barrie

ISSN:0013-9580    

DOI:10.1111/j.1528-1157.1994.tb02535.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Summary:The effect of metaphit (a phencyclidine analogue with an acylating isothiocyanate) on kindling development and kindled seizures from amygdala was investigated in rats pretreated once with metaphit. Administration of a single dose of metaphit (10 or 20 mg/kg intraperitoneally i.p.) 4 h before the first electrical stimulation of the amygdala did not in itself induce seizures, but greatly facilitated development of behavioral seizures during kindling. This effect persisted throughout the whole process of electrical amygdala kindling without further dosing. In contrast, metaphit only transiently and modestly increased the growth of afterdischarge (AD) duration. In kindled rats, pretreatment with a single dose of metaphit (20 mg/kg) 8 h before the test stimulation reduced the threshold current required to elicit a stage 5 seizure and shortened the latency for bilateral forelimb clonus (BFC) without changing AD duration or BFC duration. The facilitation of kindling development and kindled seizures may be due to an excessive excitatory transmission by metaphit in the limbic seizure circuitry.

ISSN:0013-9580    

DOI:10.1111/j.1528-1157.1994.tb02536.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Summary:D‐Cycloserine is a partial agonist of the strychnine‐insensitive glycine site that inhibits the tonic hindlimb extension (THE) component of maximal electroshock seizures (MES). This study determined the effect of focal D‐clycoserine microinfusion into nucleus re‐ticularis pontis oralis (RPO) on the THE component of MES in rats. Bilateral microinfusion of D‐cycloserine (50 nmol per side) into the RPO region 5.4 and 5.6 mm posterior to bregma inhibited THE in 80% of rats tested. Unilateral D‐cycloserine (50 nmol) RPO microinfusions were ineffective. Likewise, RPO microinfusion of vehicle, L‐cycloserine (50 nmol per side), or the strychnine‐insensitive glycine site antagonist 7‐chlorokynurenic acid (10 and 50 nmol per side) did not alter THE incidence. However, coinfusion of 7‐chlorokynurenic acid (50 nmol per side) with D‐cycloserine (50 nmol per side) completely antagonized the anticonvulsant activity induced by D‐CYcloserine (8 of 8 rats with THE). These data indicate that the anticonvulsant activity of D‐cycloserine is mediated by RPO. Because the anticonvulsant effect is stereospecific and is reversible by 7‐chlorokynurenic acid, these results also indicate that D‐cycloserine acts through the strychnine‐insensit

ISSN:0013-9580    

DOI:10.1111/j.1528-1157.1994.tb02537.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Summary:Brain glucose consumption in rats with unilateral visual cortex implants of epileptogenic cobalt rods was assessed by the 2‐deoxyglucose (2‐DG) method. Nine days postoperatively, “dark patches” of higher 2‐DG uptake, bordered by tissue showing lesser uptake, were observed around the implant site. The dark patches were located just beyond the damaged perifocal zone, in normal‐appearing Nissl‐stained cortex designated by the electrocorticographic (ECoG) work of other investigators as the focus of epileptic activity. As was also predictable from earlier research, the cortical patches were prominent on day 9 and absent by day 35. Regions of high metabolic activity in thalamus, presumably the result of axonal transport of cobalt ions, were also strikingly evident in the projection nuclei connecting with the cortical implant sites. The abnormal thalamic activity is likely the metabolic counterpart of “secondary foci,” a characteristic feature of the cobalt model. The longevity of these thalamic dark patches, which developed between days 2 and 9 and did not disappear until between days 90 and 365, may account for the persistent sensitivity to seizure‐inducing drugs that occurs secondary to cobalt implants. The absence of dark patches after control non seizure‐inducing but toxic copper implants argued against the possibility that the dark patches reflected some non‐epileptogenic effect of the cobalt. As well, under pentobarbital anesthesia, the patches behaved in a manner suggesting that their 2‐DG uptake reflected neural and not glial cell activity. Dark patches are a distinctive autoradiograph signature of tissue

ISSN:0013-9580    

DOI:10.1111/j.1528-1157.1994.tb02538.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Summary:A house‐to‐house, cross‐sectional, population study of epilepsy on 24,130 individuals of all ages from southern Pakistan indicates an age‐specific prevalence rate of 9·99 in 1,000 (14·8 in 1,000 in rural and 7·4 in 1,000 in urban areas) for recurrent, non febrile “active” epilepsy in Pakistan. Mean onset of epilepsy was 13·3 years, and 74·3% epileptic persons were aged<19 years at onset of the disorder. The most common seizure type was ton‐icclonic in 77% [primary generalized tonic‐clonic (GTC) in 59% and secondarily generalized in 18%], simple partial (SPS) in 5%, complex partial (CPS) in 6%, generalized absence in l%, tonic in 3%, and myoclonic in 3% cases. Multiple seizure types in the same person were evident in 9·6% of only the generalized group. A putative cause could be suggested in 38·4% of cases: 32% had a positive family history of epilepsy, most common among siblings. Common perceived precipitants included fever in 29·2% and emotional disturbances in 16·6%. Only 3% of epileptic persons believed that their illness was due to supernatural causes. Treatment status was very poor, with only 2% rural and 27% urban epileptic persons receiving antiepileptic drugs (AEDs) at the time of the survey. We discuss the logistic and management problems of population‐based epidemiologic studi

ISSN:0013-9580    

DOI:10.1111/j.1528-1157.1994.tb02539.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Summary:We evaluated prospectively the occurrence of seizures within 15 days of a first stroke or transient ischemic episode in 1,640 patients to study relation between seizures and type of stroke. Seizures occurred in 90 patients (5·4%), including 36 (4·4%) of 814 with infarct owing to atheroma, 21 (16·6%) of 126 with infarct owing to cardiogenic embolus, 3 (1%) of 273 owing to lacunar infarct, 5 (1·9%) of 259 owing to transient ischemic attack (TIA), 21 (16·2%) of 129 owing to supratentorial he matoma, and 4 (16·6%) of 24 owing to subarachnoid hemorrhage. Thirteen (14·6%) of 89 subcortical infarcts were associated with seizures. Seizures were the initial sign of stroke in 80 (89%) of 90 cases and were usually single and partial. Seizure symptoms were most often motor, sensory, or

ISSN:0013-9580    

DOI:10.1111/j.1528-1157.1994.tb02540.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Summary:Because disorders of neuronal migration to cerebral cortex in humans are believed to occur in the first half of gestation, prenatal events or genetic factors are suspected to have a pathogenetic role. We evaluated this by comparing the frequency of potentially harmful prenatal events and of genetic factors in a series of 40 patients (38 with epilepsy) with neuronal migration disorders (NMD) and in 40 epileptic controls, using a predetermined standardized questionnaire to minimize interviewer bias. Potentially harmful prenatal events (significant maternal physical trauma, ingestion of medications, exposure to roentgenograms, infections, uterine or metabolic abnormalities) were reported in the pregnancy histories of 58% of patients with NMD but in only 15% of epileptic controls (p = 0·0002). In contrast, peri and postnatal potentially relevant etiologic factors were reported in the histories of only 22% of patients with NMD but in 50% of the epileptic controls (p = 0·01). Genetic factors (a family history of epilepsy, mental retardation, or congenital malformations of the CNS) were noted in 13 and 20% of the families, respectively. Stillbirths occurred only in the group with NMD, accounting for 3·06% of sibling pregnancies. The findings suggest that prenatal potentially harmful environmental events play a central role in the pathogenesis of NMD in huma

ISSN:0013-9580    

DOI:10.1111/j.1528-1157.1994.tb02541.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Summary:A diffuse electrodecremental ictal pattern with other forms of epilepsy and has been considered to reflect a generalized seizure disorder of diffuse cortical or subcortical (brainstem) origin. In some seizures associated with DEP, however, focal ictal manifestations have been observed. We reviewed the records of all patients admitted to our seizure monitoring unit for 3 years and detected 39 patients with seizures associated with DEP. In 23 of 39 patients, clinical ictal behaviors resembled seizures of unilateral supero/mesiofrontal lobe origin and interictal EEG showed a prominent unilateral frontal component. Nine of 39 had complex absences (CA)/complex partial seizures (CPS); 4 of them were of unilateral frontal lobe origin. Seven of 39 patients had tonic or atonic seizures. Seven patients were studied further with subdural electrodes. Ictal onsets showed a highfrequency frontal lobe discharge. We conclude that in a subgroup of patients a generalized electrodecremental pattern on scalp EEG results from a regional cortical high‐frequency ictal discharge originating in a single frontal lob

ISSN:0013-9580    

DOI:10.1111/j.1528-1157.1994.tb02542.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY