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

The action of intravenously injected taurine, glycine and GABA has been tested on convulsions induced by strychnine using electroencephalographic and electromyographic recordings. The dose of strychnine necessary to produce a generalized tonic-clonic seizure was 0.55 +/- 0.15 mg/kg intravenously for rabbits pretreated with taurine, which was significantly higher than for control animals (0.38 +/- 0.13 mg/kg). After pretreatment with glycine, the strychnine dose required to evoke convulsions (0.51 +/- 0.22 mg/kg) was also higher than the control values, but the difference was statistically not significant. The convulsive dose of strychnine in animals pretreated with GABA was slightly but not significantly lower than in control animals (0.31 +/- 0.13 mg/kg). These results suggest that taurine is the most effective amino acid to protect rabbits from seizures induced by strychnine.
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PMID:Effects of taurine, glycine and GABA on convulsions produced by strychnine in the rabbit. 43 61

The administration of L-alpha-amino-beta-chloropropionic acid hydroxamide (L-ACPH) to mice brought about an inhibition in GABA-T activity in the brain of the animals, a significant inhibition occurring with dosage levels as low as 0.25 mmol/kg. Minimum levels of GABA-T activity were reached 3 h after administration of the drug. Brain glutamic acid decarboxylase, DOPA decarboxylase and aspartate aminotransferase activities were not altered by the L-ACPH but alanine aminotransferase activity was totally inhibited. Slight changes in structure caused great changes in the potency of the drugs. For example, the elongation of the L-ACPH structure by one carbon, or a change in the configuration of the amino group from L- to D-, caused a significant decrease in GABA inhibition. The chloro and hydroxamide groups were necessary for inhibitory activity. The administration of L-ACPH to mice delayed the onset of drug induced seizures but had a less noticeable effect against maximal electroshock. The addition of L-ACPH to crude extracts from brain, or to preparations of semipurified GABA-T, also inhibited GABA-T activity. Again the development of the inhibition was time-dependent. Possible mechanisms of action with respect to L-ACPH induced inhibition of GABA-T activity are discussed in the light of the data presented.
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PMID:Alteration of GABA metabolism in mammalian brain by l-alpha-amino-beta-chloropropionic acid hydroxamide and related compounds. 45 23

The hypothesis that the seizure susceptibility of chronically denervated cortex is due to interruption of recurrent inhibitory pathways was tested by examining the release of 3H-labeled gamma-aminobutyric acid ([3H]GABA) from chronic slabs and normal cortex of cats. Seizure activity was maintained throughout the test periods in both normal and chronically isolated cortex. When methacholine was used to evoke seizure activity, [3H]GABA release was depressed in both normal and epileptic cortex, suggesting that the mechanism of seizure genesis by cholinomimetics involves suppression of inhibitory neuron activity. Pentylenetetrazol-induced seizures evoked a small, equal increase in [3H]GABA efflux from epileptic and normal cortex. Continuous electrical stimulation evoked a large, and again equal increase in [3H]GABA release. Preseizure efflux of [3H]GABA was the same from chronic slabs and normal cortex in all experiments. Since the interruption of recurrent inhibitory pathways by chronic denervation would result in a decreased resting and seizure-evoked release of [3H]GABA, results obtained do not support the above-mentioned hypothesis.
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PMID:Release of exogenous gamma-[3H]aminobutyric acid during seizure activity in chronically denervated and normal cat cortex. 49 93

Pretreatment of adult male Sprague-Dawley rats with a single dose of gamma-vinyl GABA (GVG) (1200 mg/kg, IP) or gamma-acetylenic GABA (GAG) (100 mg/kg, IP) did not affect the threshold of metrazol-activated generalized seizures, but increased their duration to the point of status epilepticus. In rats with epilepsy kindled by amygdaloid stimulation, a single dose of GVG (800 mg/kg, IP) and five subsequent daily administrations of GAG (80 mg/kg, IP) tended to reduce the motor manifestations of seizures leaving unaffected their electrographic pattern. The effects of GVG and GAG are attributed in part to decreased arousal. Practical implications of these findings are discussed.
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PMID:Effects of gamma-acetylenic GABA and gamma-vinyl GABA on metrazol-activated, and kindled seizures. 50 7

Compounds blocking the uptake of GABA into neurons or glia have been injected intracerebroventricularly (icv) or intraperitoneally (ip) in DBA/2 mice, age 21-28 days. Protection against audiogenic seizures was seen 30 min after the icv injection of (+)-2,4-diaminobutyric acid (0.5-2.0 mumoles), (+/-)-nipecotic acid (1.6-3.2 mumoles), (+)-ethyl nipecotate (0.4-0.8 mumoles), (-)-piperazic acid (4 mumoles) and putrescine (2 mumoles) or the ip injection of (+)-2,4-diaminobutyric acid (4-8 mmoles/kg and (+)-ethyl nipecotate (0.24-0.32 mmoles/kg). Of these ethyl nipecotate and nipecotic acid were the most effective anticonvulsants icv, but nipecotic acid was ineffective ip. Limb myoclonus and other epileptic manifestations (rearing, wild running, tonic clonic seizures) occurred in the absence of auditory stimulation after (+)-2,4-diaminobutyric acid (0.5-2.0 mumoles), (+/-)-cis-3-aminocyclohexane carboxylic acid (3.2-6.4 mumoles) and putrescine (2 mumoles). beta-Alanine (2-4 mumoles, icv) depressed respiration but did not protect against audiogenic seizures or induce myoclonus.
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PMID:Convulsant and anticonvulsant actions in DBA/2 mice of compounds blocking the reuptake of GABA. 51 Apr 1

The seizure susceptibility to electroshock in mice is decreased by apomorphine and piribedil; the effect of the two dopaminergic agonists is reduced by haloperidol. The seizure susceptibility is not influenced, increased or reduced by the different doses of haloperidol. The seizure threshold is elevated by amino-oxyacetic acid; its effect is reduced by picrotoxin, haloperidol and reserpine, and not influenced by apomorphine. The interaction between dopaminergic and GABA-ergic systems has been established; however, its characteristics are different from the well known interaction in the nigrostriatal region.
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PMID:Role of dopaminergic and GABA-ergic interactions in seizure susceptibility. 52 81

Mice were made physically dependent on ethanol by a 3-day period of alcohol inhalation with small daily injections of pyrazole. During this treatment the concentrations of norepinephrine, dopamine and 5-hydroxytryptamine were increased in brain with concomitant decrease in gamma-aminobutyric acid, RNA and DNA. However, the monoamine concentrations showed complete regression to normal levels at the time of maximal withdrawal seizure when GABA level was still elevated above the control values. Brain RNA and DNA concentrations remained low at this period. During the recovery phase, the pattern of neuronal components was almost the same as was observed at maximal withdrawal seizures. Pyrazole by itself did not produce significant changes in concentrations of the neuronal components of brain.
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PMID:Neurochemical aspects of ethanol dependence and withdrawal reactions in mice. 55 9

In order to examine the behavioral and physiologic consequences of chronic activation of the mesolimbic dopamine system, the nucleus of origin in the ventral tegmental area was stimulated electrically for 2 seconds daily through chronically implanted intracranial electrodes in cats at the same point where instillation of the GABA blocking agent bicuculline induced a characteristic fear, staring, searching, and withdrawal response. None of the animals developed sustained after-discharge or seizures following daily stimulation for 2 months. Progressive fearfulness, hiding, loss of social behavior, and EEG spike or slow activity in the ipsilateral nucleus accumbens developed in three of six intact animals. Two cats with prior 6-hydroxydopamine lesions of catecholamine pathways did not develop behavioral change in response to local bicuculline or daily electrical stimulation of the ventral tegmental area but demonstrated pronounced after-discharge or EEG spike propagation during the kindling procedure.
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PMID:Kindling of the mesolimbic dopamine system: animal model of psychosis. 56 37

A 13 1/2-year-old child died with vitamin B6-dependent seizures in progress. Microscopic findings in brain included an abnormally sparse quantity of central myelinated fibers in the cerebral hemispheres. Glutamic acid concentrations were elevated and GABA concentrations reduced in the frontal and occipital cortices but not in the spinal cord. All other amino acid concentrations were normal, except for increased cystathionine in the occipital cortex. Pyridoxal-5-phosphate (PLP) was reduced in the frontal cortex. Glutamic acid decarboxylase activity comparable to that of controls was detected when the PLP concentration was greater than 0.05 mM. These findings suggest that pyridoxine-dependent seizures in man are associated with reduced GABA concentrations in the brain and with diminished central white matter structures.
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PMID:Vitamin B6-dependent seizures: pathology and chemical findings in brain. 56 38

Allylglycine, an inhibitor of GABA synthesis, produces increased sensitivity to photic stimulation and in convulsant doses spontaneous seizures arising occipitally in the baboon (Horton and Meldrum, 1973). In this study, convulsant doses of allylglycine induced either sharp wave and polyspike frontorolandic discharges (FR) or critical posterior discharges which then reinforce the fronto-rolandic spikes. A seizure may then arise from the fronto-rolandic region and secondarily spread to the rest of the cerebral cortex. Intermittent photic stimulation produces a reinforcement of the fronto-rolandic sharp waves and can also induce self-maintaining mechanisms similar to those just described. In this situation, however, and with the animals paralysed with Flaxedil no seizures arising occipitally have been observed. The role of the occipital cortex as the sensory visual and somatic afferent in photosensitive epilepsy in the baboon is discussed in the light of these results.
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PMID:[The induction of seizures in "Papio papio" following allylglycine alone or in combination with intermittent photic stimulation (author's transl)]. 59 66


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