Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Male mice (25-30 g) were injected (ip) with 0, 3.5 X 10(-6), or 17.5 X 10(-6) mol trimethyltin bromide (TMT), triethyltin bromide (TET), tri-n-propyltin chloride (TPT), or tri-n-butyltin bromide (TBT) per kg. Additional groups of mice were also injected (ip) with either 0 or 17.5 X 10(-6) mol sodium bromide (NaBr) or 17.5 X 10(-6) mol stannic bromide (SnBr4) per kg. The mice were tested with maximal electroshock seizure (MES) at 0.5, 4, 21-24, and 96 h following exposure to the organotin compounds. Mice exposed to TMT, TET, TPT, or TBT exhibited dose-dependent decreases in MES severity as evaluated by seizure-grade distributions and duration of tonic seizure phases. The tri-n-alkyltin compounds exhibited a structure-activity relationship in their ability to decreased maximal responsiveness to the MES test. In order of decreasing ability they were: TMT greater than TET greater than TPT greater than TBT. Administration of NaBr and SnBr4 did not alter MES responsiveness, indicating the essential role of the alkyl moieties of the tri-n-alkyltin compounds in producing alterations in central nervous system function.
 ...
PMID:Effects of organotin compounds on maximal electroshock seizure (MES) responsiveness in mice. I. TRI(n-alkyl)tin compounds. 713 88

1. The temporal lobe status appears at a rate of once every 3-5 minutes. 2. The duration of a single temporal lobe seizure is varied, ranging from 10 seconds to 140 seconds. 3. The EEG during seizures is characterized by a generalization of 15-32 Hz recruiting epileptic rhythm which may become 3-7 Hz slow waves later in some cases, 3-7 Hz paroxysmal rhythmic waves. 4. The clinical symptoms are colorful, including apnic seizures, verbal automatism, facial muscle twitching, versive seizure and tonic seizure. The clinical symptoms depend on the size and depth of focus and the scope of propagation of discharge. 5. Generalization cannot be attained merely by the firing of focus that has been formed secondarily. The firing of primary focus is indispensable as the condition for generalization. 6. The focus depends more on the time of the disappearance of discharges than on the site of the primary onset of paroxysm. Particularly important is the length of duration of ictal discharges. 7. The cortico-cortical synapse and the cortico-subcortical pathways were considered the sources of epileptic propagation.
 ...
PMID:Clinical and electroencephalographic study of temporal lobe status. 721 66

The use of benzodiazepines (BDZs) in the long-term treatment of epilepsy is greatly restricted by their capacity to induce tolerance and dependence. Thus, the development of new BDZ-related therapeutic agents should be directed by strategies that minimize tolerance- and dependence-inducing properties. Experimental procedures used to determine the success of such strategies often rely on a single assay procedure (e.g., one seizure model), which might lead to false predictions. Furthermore, the different types of tolerance, i.e., "pharmacological" (metabolic or functional) and "behavioral" ("learned" or "contingent"), are often not dealt with in such studies. This prompted us to compare the chronic anticonvulsant efficacy and withdrawal characteristics of diazepam and two novel BDZ receptor ligands, i.e., the partial agonist bretazenil and the subtype-selective agonist abecarnil, in different seizure models in mice. Myoclonic, clonic and tonic seizures were induced by i.v. infusion of pentylenetetrazol and by transcorneal or transauricular application of electrical stimuli. Prolonged administration of diazepam (5 mg/kg twice daily for 6 days) resulted in marked anticonvulsant effects on myoclonic, clonic and tonic seizure thresholds at the onset of treatment, but pronounced tolerance developed rapidly during subsequent treatment. The time course and extent of tolerance was similar with most seizure models. Tolerance characteristics were not affected by study design, i.e., use of separate or the same animals for each seizure induction, indicating that learned or contingent tolerance was not significantly involved under these experimental conditions. After termination of treatment with diazepam, significant seizure threshold decreases were determined, indicating withdrawal hyperexcitability in response to physical dependence. During prolonged administration of abecarnil (10 mg/kg twice daily for 6 days), some anticonvulsant tolerance was seen with electroshock seizures, but not with pentylenetetrazol seizures; no withdrawal hyperexcitability was determined upon termination of treatment. Bretazenil (10 mg/kg twice daily for 6 days) produced no tolerance in any of the seizure models, but a significant decrease in electroshock seizure threshold was seen in the withdrawal period. The data indicate that tolerance and withdrawal characteristics of BDZ receptor partial and subtype-selective agonists in mice depend on the experimental model used, whereas the influence of the experimental protocol is less critical in the case of a full BDZ receptor agonist such as diazepam.
 ...
PMID:Anticonvulsant tolerance and withdrawal characteristics of benzodiazepine receptor ligands in different seizure models in mice. Comparison of diazepam, bretazenil and abecarnil. 747 56

The relation between hypoxia/ischemia and subsequent alterations in seizure susceptibility in developing brain remains unclear. We assessed the behavioral and electrocorticographic (ECoG) effects of hypoxic/ischemic brain damage on bicuculline (BIC)-induced seizures in 7-day postnatal rats, and determined maturational changes in seizure susceptibility, behavior and ECoG activity. Rat pups were subjected to unilateral common carotid artery ligation, followed by exposure to 8% O2 at 37 degrees C for 2 h, an insult that produces brain damage in the cerebral hemisphere ipsilateral to carotid artery occlusion. The experimental group consisted of rat pups previously subjected to hypoxia/ischemia; control littermates received neither arterial ligation nor systemic hypoxia. Experimental animals received 4, 5, or 6 mg/kg BIC subcutaneously (s.c.) at 2 and 24 h, and at 3, 7, and 21 days of recovery from hypoxia/ischemia. Two animals at each interval of recovery, 1 each from the experimental and control groups, were used for ECoG monitoring. After BIC injection, animal behavior was observed for 2 h. Behaviors and seizures were classified in five categories based on severity, duration, and character: 1, mild irritability; 2, few clonic seizures and agitation; 3, few tonic-clonic seizures with swimming movements; 4, frequent tonic-clonic seizures with apneic episodes; 5, continuous tonic-clonic seizures and death. Rat pups previously subjected to hypoxia/ischemia had lesser seizure susceptibility than controls at 2-h recovery (p < 0.05) and greater susceptibility than controls at 24 h (p < 0.05). Tonic seizures were prominent at 2 and 24 h in both the experimental and control groups, whereas lesion-sided circling was prominent only in the hypoxic/ischemic rat pups.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Effect of hypoxia/ischemia on bicuculline-induced seizures in immature rats: behavioral and electrocortical phenomena. 760 19

We examined the effect of interpeduncular nucleus (IPN) kindling on subsequent amygdala (AM) kindling in rats (n = 9). Eleven to 15 daily IPN stimulations at an afterdischarge (AD)-inducing threshold (400-1000 microA, biphasic sine waves, 1-3 s) produced progressive AD growth (9 of 9 rats) and recruitment of behavioral seizures (7 of 9 rats). The final form of the latter was generalized tonic-clonic seizures with or without a limbic seizure component. The latter was associated with ictal involvement of AM and sensorimotor cortex. Subsequent AM kindling resulted not only in more rapid kindling, but also in tonic seizure associated with a protracted loss of postural control (5-20 s) not observed in animals undergoing AM kindling without previous IPN kindling (n = 5). These findings indicate that the IPN can be kindled and that subsequent AM kindling utilizes the proconvulsant neuroplastic changes that have been already established by IPN kindling.
 ...
PMID:Kindling of the interpeduncular nucleus and its influence on subsequent amygdala kindling in rats. 760 21

A possible relationship among cyanide-induced convulsions, calmodulin, nitric oxide and protein kinase C was investigated in mice. The ED50 value of cyanide as measured by induction of tonic seizures was significantly increased in a dose-dependent manner when mercuric chloride (0.5 or 5.0 nmol/body), gangliosides (GGS) (90 nmol/body), a protein kinase C inhibitor or trifluoperazine (TFP) (45 or 90 nmol/body), a calmodulin inhibitor were preinjected intracerebroventricularly (i.v.t.) and NG-nitro-L-arginine (NNA) (300 mg/kg), a nitric oxide (NO) synthase inhibitor was preinjected intraperitoneally (i.p.) in mice. These results suggest that protein kinase C, calmodulin, and NO dependent cyclic guanosine monophosphate (GMP) dependent enzymes may contribute to the induction of convulsions. In contrast, 2,4-dinitrophenol (DNP) (50 nmol/body, intracerebroventricularly (i.v.t.), an uncoupler of oxidative phosphorylation significantly decreased the ED50 value of cyanide. In addition, DNP (100 nmol/body, i.v.t.) produced a severe tonic seizure in all of the treated mice. These indicate that adenosine triphosphate (ATP) depletion may also contribute in part to the development of cyanide-induced convulsions.
 ...
PMID:A hypothesis for cyanide-induced tonic seizures with supporting evidence. 782 86

In common with other dysmyelinating mutants, the myelin-deficient rat displays an action tremor and tonic seizures culminating in the death of the animals at approximately 23-26 days. We find that deep lesions of the cerebellar vermis alleviate the manifestations of the myelin deficiency significantly. Such lesions introduced at 20 days or later eliminate both tremor and seizures for periods up to 10 days. Lifespan is prolonged to nearly 30 days, on average, and to 35 days in some cases. Shallow lesions of the vermis or lateral lobe lesions have relatively little effect. Based on these observations we suggest that the cerebellum contributes not only to the action tremor but also to the tonic seizures characteristic of central myelin deficiency. Spontaneous activity originating in myelin-deficient fiber tracts may be carried to the cerebellum and processed there to produce a highly amplified and/or synchronized output to broad areas of the neuraxis. Deep lesions of the vermis presumably interfere with cerebellar output and compromise the cerebellar contribution to the seizures. Tonic seizures and other 'paroxysmal attacks' also occur commonly in human demyelinating diseases including multiple sclerosis [11]. Manipulation of cerebellar output offers a potential approach to the control of such spontaneous activity.
 ...
PMID:Effects of cerebellar lesions on tonic seizures, tremor and lifespan in myelin-deficient rats. 795 81

Experiments on male Wistar rats and Icr:Icl mice studied the influence of the novel compound--amino acid-containing 1,4-dihydropyridine derivative glutapyrone (G) on acute generalized seizures, arecoline and nicotine tremor, and 45Ca2+ uptake in brain synaptosomes. It was shown that G produced significant antiepileptic effects on models of acute pentylenetetrazole seizures on rats and mice. Efficiency of antiepileptic effect depended on a dose and method of modeling seizures: it was more effective in case of intravenously pentylenetetrazole-induced seizure tested by clonic and tonic seizure components and death. The results suggest the participation of GABAergic system in realization of antiepileptic effect of G. Glutapyrone did not influence the 45Ca2+ uptake by rat cortical synaptosomes (evoked by a 1-min depdariration with 55 mM K+), this suggests that G lacked calcium antagonist properties characteristic of 1,4-dihydropyridine compounds such as nifedipine, nimodipine. In addition, G does not affect N- and M-cholinergic processes.
 ...
PMID:[The anticonvulsant properties of glutapyrone--a new type of derivative of amino acid-containing 1,4-dihydropyridines]. 811 3

Spontaneously epileptic rats (SER) are a double mutant (zi/zi, tm/tm) obtained by mating the tremor rats with another tremulous mutant, zitter rats, and spontaneously exhibit absence-like seizures, tonic convulsions and wild jumping or running episodes. In addition, SER exhibit retardation in learning ability under differential reinforcement at a low rate (DRL)-5 sec schedule of food reinforcement in operant behavior at 14 to 15 weeks of age. We examined the long-term effects of phenobarbital (PB) on total bar presses, reinforcements and inter-response time distribution to assess whether the poorness of learning ability in SER can be ascribed to frequent occurrence of seizures. Food pellets containing 0.1% PB were given ad libitum to male SER from 7 weeks, and operant behavior was examined at 13 to 14 weeks of age. Tonic seizures and wild jumping or running episode were inhibited effectively and poor operant performance was significantly improved by continual intake of PB in SER.
 ...
PMID:Improvement of poor operant performance by continual intake of phenobarbital in spontaneously epileptic rats. 811 37

The cerebellum is electrically and metabolically active during seizures. Numerous studies have also shown that cerebellar electrical stimulation and lesions of the cerebellar cortex or nuclei influence seizure threshold, but there are significant contradictions, with different effects observed even in investigations using the same species and similar seizure types and experimental manipulations. Discrete intracerebral microinjection of neuroactive agents has been used to characterize the way in which other brain regions control seizures, but has not been applied to the cerebellar systems. This approach has advantages because effects are restricted to specific receptors and spare passing axons; experimental variables also can be simply specified and reproduced. We used this method to characterize the role of the cerebellar nuclei in seizures and to determine if observed effects could be reproduced with different agents at different doses. Effects of bilateral control microinjections in the fastigial (medial) cerebellar nucleus were compared with different doses of the GABAA agonist piperidine-4-sulfonic acid and the GABAB agonist (-)baclofen (Bf). Soon after injection, the animals were ataxic. After 4 min, seizures were induced by timed continuous intravenous (i.v.) bicuculline (BIC) infusion. Both GABA agonists produced significant reductions in myoclonic, clonic, and tonic seizure thresholds. Injections just dorsal or anterior to this nucleus and bilateral dentate (lateral) nucleus injections had little effect on seizures. These results demonstrate that the cerebellar system does control seizures, but does not provide support for the early concept that cerebellar stimulation and systemic phenytoin block seizures through inhibition of cerebellar nuclei secondary to Purkinje cell activation.
 ...
PMID:Role of the fastigial nucleus in generalized seizures as demonstrated by GABA agonist microinjections. 824 71


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>