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Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The anticonvulsive properties of orally administered cinnarizine [(E)-1-(diphenylmethyl)-4-(3-phenyl-2-propenyl)-piperazine], its difluoro derivative flunarizine [(E)-1-(bis-(4-fluorophenyl)methyl)-4-(3-phenyl-2-propenyl)-piperazine], diphenylhydantoin and phenobarbital, were studied against maximal metrazol seizures (MMS) in rats and maximal electroshock seizures (MES) in mice. In rats (MMS), the lowest ED50 for protection against tonic extension of hindpaws was 4.10 mg/kg (1 h 35 min after treatment) with sodium phenobarbital, 6.04 mg/kg (5 h 45 min) with flunarizine dihydrochloride, 9.84 mg/kg (2 h 34 min) with cinnarizine and 19.30 mg/kg (3 h 38 min) with diphenylhydantoin. In mice (MES), protection against tonic extension of hindpaws was (2 h after treatment) 7.0 mg/kg with diphenylhydantoin, 13.2 mg/kg with sodium phenobarbital, 20.9 mg/kg with flunarizine kihydrochloride and 49.0 mg/kg with cinnarizine. Except at subtoxic doses no side effects were observed in rats and mice given cinnarizine, flunarizine kihydrochloride or kiphenylhydantoin. Phenobarbital induced ataxia in rats and mice at 22 mg/kg and 42.7 mg/kg, respectively, and loss of righting reflex at 112.8 mg/kg and 160 mg/kg, respectively. Flunarizine is the longest-acting drug and has the slowest onset. At a dose of twice the minimal ED50 flunarizine affords protection against tonic extension of hindpaws in rats (MMS) for 23 h 30 min dephenylhydantoin for 11 h 38 min, phenobarbital for 8 h 22 min and cinnarizine for 8 h 16 min. Peak effect was reached with flunarizine at 5 h 45 min, with diphenylhydantoin at 3 h 38 min, with cinnarizine at 2 h 34 min and with phenobarbital at 1 h 35 min. The anti-MMS profiles of cinnarizine and flunarizine resemble that of dephenylhydantoin as all three compounds are selective blockers of tonic extension of hindpaws. Phenobarbital antagonized the whole MMS-pattern, i.e., tremors, clonic convulsions and tonic extension of fore- and hindpaws. However, the effects of phenobarbital against tremors, clonic convulsions and tonic extension of forepaws may reflect more a general CNS-depressant effect than a specific anticonvulsive activity since neurotoxic effects (ataxia and loss of righting reflex) appear at the same doses.
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PMID:Anticonvulsive properties of cinnarizine and flunarizine in rats and mice. 124 63

1. An attempt was made to evaluate the pathophysiology of symptoms of hyponatremia as related to changes in brain water and electrolytes. Studies were carried out in 66 hyponatremic patients and 5 groups of experimental animals. 2. In hyponatremic patients, symptoms (depression of sensorium, seizures) correlated well with plasma Na+ (r = 0.64, p less than .001), but there was substantial overlap. In patients with acute hyponatremia, all were symptomatic and 50% died. Among patients with hyponatremia of at least 3 days duration, sympatomatic patients had plasma Na+ (115 +/- 1 mEq/L) which was significantly less (p less than .001) than that of asymptomatic patients (plasma Na+ = 122 +/- 1 mEq/L). Among symptomatic patients, mortality was 12% and 8% had seizures, while none of the asymptomatic patients died or had seizures. 3. Among 14 patients with acute (less than 12 hrs) hyponatremia, the mean plasma Na+ was 112 +/- 2 mEq/L. All such patients had some depression of sensorium and four had grand male seizures. Seven of these patients were treated with hypertonic (862 mM) NaCl, while four were treated only with fluid restriction. Of the seven patients treated with hypertonic NaCl, five survived, while three of four patients treated with fluid restriction died. There was no evidence of circulatory congestion or cerebral damage in the patients treated with hypertonic NaCl. 4. Among rabbits with acute (2-3 hours) hyponatremia (plasma Na+ = 119 +/- 1 mEq/L), all had grand mal seizures and 86% died. All such animals had cerebral edema (brain H2O content 17% above control value) but brain content of Na+, K+ and Cl- was normal. 5. Rabbits with 3 1/2 days of hyponatremia (plasma Na+ = 122 +/- 2 mEq/L) appeared to be asymptomatic, even though brain water content was 7% above normal (p less than .01). 6. Rabbits with 16 days of more severe hyponatremia (plasma Na+ = 99 +/- 3 mEq/L) were weak, anorexic, lethargic and unable to walk. Brain water content was 7% above normal, although brain osmolality (218 +/- 12 mOsm/kg H2O) was similar to plasma (215 +/- 8 mOsm/kg). Brain content of Na+, K+, Cl- and osmoles was 17 to 37% less than normal values, so that the brain established osmotic equilibrium with plasma primarily by means of a loss of electrolytes. 7. These studies suggest that in patients with hyponatremia, symptoms and morbidity are only grossly correlated with either magnitude or duration of hyponatremia. Symptoms appear to correlate best with the interplay between a net increase in brain water versus a loss oof brain electrolytes. However, even asymptomatic animals have subclinical brain edema when plasma Na+ is below 125 mEq/L, and such edema may cause permanent brain damage. Thus, many patients with similar levels of plasma Na+, particularly when they are symptomatic, should probably be treated with hypertonic NaCl infusions.
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PMID:Neurological manifestations and morbidity of hyponatremia: correlation with brain water and electrolytes. 125 11

Potassium is tightly regulated within the extracellular compartment of the brain. Nonetheless, it can increase 3- to 4-fold during periods of intense seizure activity and 10- to 20-fold under certain pathological conditions such as spreading depression. Within the central nervous system, neurons and astrocytes are both affected by shifts in the extracellular concentration of potassium. Elevated potassium can lead to a redistribution of other ions (e.g., calcium, sodium, chloride, hydrogen, etc.) within the cellular compartment of the brain. Small shifts in the extracellular potassium concentration can markedly affect acid-based homeostasis, energy metabolism, and volume regulation of these two brain cells. Since normal neuronal function is tightly coupled to the ability of the surrounding glial cells to regulate ionic shifts within the brain and since both cell types can be affected by shifts in the extracellular potassium, it is important to characterize their individual response to an elevation of this ion. This review describes the results of side-by-side studies conducted on cortical neurons and astrocytes, which assessed the effect of elevated potassium on their resting membrane potential, intracellular volume, and their intracellular concentration of potassium, sodium, and chloride. The results obtained from these studies suggest that there exists a marked cellular heterogeneity between neurons and astrocytes in their response to an elevation in the extracellular potassium concentration.
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PMID:Effect of elevated potassium on the ion content of mouse astrocytes and neurons. 129 76

Magnesium is an essential cofactor for many enzymatic reactions, especially those involved in energy metabolism. Deficits of magnesium are prevalent due to inadequate intake or malabsorption and due to the renal loss of magnesium that occurs in certain disease states (alcoholism, diabetes) and with drug therapy (diuretics, aminoglycosides, cisplatin, digoxin, cyclosporin, amphotericin B). Protracted deficits of magnesium in humans and animals result in neurological disturbances, including hyperexcitability, convulsions and various psychiatric symptoms ranging from apathy to psychosis, some of which can be reversed with magnesium supplementation, others requiring correction of the dysregulation mechanism. Although the role of magnesium in neuronal function is not completely understood, a lowering of CSF or brain magnesium can induce epileptiform activity and there is an association between decreased CSF magnesium and the development of seizures. CSF concentrations of magnesium are normally higher than magnesium plasma ultrafiltrate (diffusible) concentrations due to the active transport of magnesium across the blood-brain barrier. Under conditions of magnesium deficiency, CSF concentrations decline, although this decline lags behind and is less pronounced than the changes observed in plasma magnesium concentrations. Decreases in CSF magnesium concentrations correlate with the alterations observed in extracellular brain magnesium concentrations in animals following the dietary deprivation of magnesium. CSF magnesium concentrations can readily be repleted following magnesium supplementation, although high dose magnesium therapy, such as that used in the treatment of convulsions in eclampsia, will only increase CSF magnesium concentrations to a very limited degree (approximately 11-18 per cent) above physiological concentrations. Greater increases in CSF magnesium may occur in neonates since neonatal swine, following treatment with magnesium, have CSF magnesium concentrations that are similar to their plasma concentrations. There has been a recent resurgence of interest in magnesium deficiency and its neurological consequences due to the finding that magnesium, at physiological concentrations, blocks N-methyl-D-aspartate (NMDA) receptors in neurones. NMDA receptors are normally activated by glutamate and/or aspartate which represent the principal neurotransmitters for excitatory synaptic transmission in vertebrate CNS. Magnesium deficiency produces epileptiform activity in the CNS which can be blocked by NMDA receptor antagonists. Other mechanisms, including alterations in Na+/K(+)-ATPase activity, cAMP/cGMP concentrations and calcium currents in pre- and postsynaptic membranes, may also be at least partially responsible for the neuronal effects associated with low brain magnesium. Further studies are necessary to increase our understanding of the neurological implications of magnesium deficit in the central nervous system.
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PMID:Brain and CSF magnesium concentrations during magnesium deficit in animals and humans: neurological symptoms. 129 67

Cognitive function of patients on monotherapy specific for their epileptic syndrome has been studied infrequently. We evaluated 7 patients with symptomatic localised epilepsies (SEL) on phenytoin aged 30 +/- 12 (mean +/- standard deviation) years, 8 with idiopathic generalised epilepsies on sodium valproate aged 18 +/- 4 years, 16 with SEL on carbamazepine aged 28 +/- 11 years, and 35 healthy controls aged 27 +/- 11 years. All subjects were of normal intelligence, educated appropriately to age, and led productive lives in the community. Two of the patients on carbamazepine and one on valproate had less than five partial, absence or myoclonic seizures monthly, the remaining were controlled. Carbamazepine serum concentrations were 12 +/- 5 micrograms/ml, phenytoin were 23 +/- 7, and valproate were 62 +/- 23 (mean +/- sd). Tests included immediate recall and recognition for pictures, Stroop test, delayed recall and recognition of pictures. Patients on phenytoin and valproate performed significantly worse than controls on immediate recall, and patients on carbamazepine performed significantly worse than controls in Stroop test (p < 0.01). The results indicate relatively minor effects of the epileptic syndromes and of phenytoin, carbamazepine and valproate on cognition of patients with controlled epilepsy leading productive lives in the community. We conclude that the cognitive deficit found in chronic epileptic patients on poly-therapeutic drug regimen must be multifactorial, and that future studies need to control for all possible variables in order to achieve meaningful results.
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PMID:Cognitive functions, epileptic syndromes and antiepileptic drugs. 130 74

The serum valproate (VPA) concentration and the clinical effects of polytherapy with other antiepileptic drugs: phenobarbital (PB), clonazepam (CZP), diazepam (DZ), clobazam (CLO), ethosuximide (ESX) were estimated. VPA serum levels were reduced when this drug was combined with phenobarbital. Clobazam given together with valproate led to an increase in the serum concentration of the former drug. VPA serum levels were without significant changes when the drug was combined with either ethosuximide or 1-4-benzodiazepines. The best therapeutical effects were found after polytherapy sodium valproate with ethosuximide and clobazam in primary generalized seizures.
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PMID:Certain aspects of interaction between sodium valproate and other anticonvulsant drugs in the therapy of epilepsy in children. 130 65

The first and second child of a family died from neonatal seizures with no detectable brain malformation, metabolic, infectious, or chromosomal etiology. Neuropathological examination of the brain of the second child who died at 11 days revealed a widespread spongy state and a selective vulnerability of the astrocytes characterized by numerous enlarged bare astrocytic nuclei and different forms of astrocyte degeneration. The glial cells were strongly positive for glial fibrillary acidic protein and vimentin immunocytochemical reaction. Cortical measurement of Na+/K(+)-ATPase revealed very low enzyme activity. We hypothesize that a defect of Na+/K(+)-ATPase of the astrocytes could be the common pathogenetic factor for the congenital status convulsivus and for the spongy state.
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PMID:Neonatal status convulsivus, spongiform encephalopathy, and low activity of Na+/K(+)-ATPase in the brain. 131 Feb 85

A 63-year-old white female who was being treated for hypertension with lisinopril presented with seizures, altered mental status, and a serum sodium of 101 mEq/L. Serum sodium prior to initiation of lisinopril therapy was 137 mEq/L. The hyponatremia was corrected and did not recur after lisinopril was stopped. The hyponatremia may have been a result of polydipsia and inappropriate antidiuresis secondary to ACE-inhibitor therapy.
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PMID:Case report: severe symptomatic hyponatremia associated with lisinopril therapy. 131 75

A double-blind trial was done in 228 patients with one single seizure 2 weeks before coming to the author. One group was given sodium valproate, the other group placebo. The duration of therapy was 12 months. The results of this trial show that a person with a single seizure has epilepsy and should be treated with sodium valproate.
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PMID:First seizure in adults: to treat or not to treat. 132 May 21

Ralitoline, a thiazolidinone derivative chemically distinct from known antiepileptic drugs, possesses remarkable anticonvulsant properties as demonstrated in various animal models of epilepsy. The efficacy of this compound seems to be comparable or even better than that of conventional antiepileptics. In the present study, the activity of ralitoline was investigated in four seizure models in rodents in order to characterize the anticonvulsant profile of action further. In the maximal electroshock seizure test (mice), this compound showed marked anticonvulsant effects (ED50 2.8 mg/kg i.p.). The efficacy of clinically established anti-epileptics was significantly increased when ralitoline was given as co-medication. In the strychnine seizure test (mice), ralitoline (5 and 10 mg/kg) prolonged the latency of tonic seizures as well as the survival time. On the other hand, in the subcutaneous pentylenetetrazol seizure threshold test (mice), this drug revealed limited protective actions at higher doses and increased the effectiveness of ethosuximide. In unrestrained rats with chronically implanted electrodes, ralitoline (5 mg/kg) significantly reduced the duration of electrically-evoked hippocampal discharges and raised the focal stimulation threshold (10 mg/kg). In the rotorod ataxia test (mice), a TD50 value of 14.5 mg/kg i.p. was determined for ralitoline (protective index TD50/MES-ED50 5.2). With regard to the possible mode of action, whole-cell voltage-clamp experiments on cultured neonatal rat cardiomyocytes showed that ralitoline may act specifically on voltage-sensitive sodium channels. The compound inhibited the fast sodium inward current in a frequency- and voltage-dependent manner. In conclusion, the findings confirm the potent anticonvulsant effects of ralitoline, especially against generalized tonic-clonic and complex partial seizures. Moreover, in combination with antiepileptics, an additive synergism can be found at lower concentrations. Regarding the mode of action, this drug was capable of depressing the fast sodium inward current in cultured heart ventricular cells, suggesting that the local anesthetic properties may be important for the anticonvulsant activity of ralitoline.
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PMID:Anticonvulsant and sodium channel blocking effects of ralitoline in different screening models. 133 17


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