Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027066 (myoclonus)
 4,275 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The kindling response of the lateral geniculate body (GL) was compared with that of the amygdala, using cats. Daily electrical stimulation in the GL group led to the generalized tonic-clonic convulsion in most subjects and the resulting state of seizure susceptibility was long-lasting, as in the amygdala group. The kindling response of the GL differed from that of the amygdala in some respects, i.e., rapid kindling, short latency for seizure generalization, a different pattern of behavioral seizure development, and seizure regression during the course of kindling. The effects of photic stimulation with pentylenetetrazol administration were also examined before and after kindling in both groups. This study revealed that the photically induced myoclonus, at times proceeding to the generalized tonic-clonic convulsion, was provoked repeatedly as a result of GL kindling, whereas none of the amygdala-kindled cats showed such marked photosensitivity. These photically induced seizures were invariably observed for at least 4 weeks after GL kindling. Our results suggest that a neural mechanism participating in GL kindling is different from that in amygdala kindling, and that there might be cross-sensitization between seizure susceptibility resulting from GL kindling and photosensitivity.
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PMID:Lateral geniculate kindling and long-lasting photosensitivity in cats. 394 78

Uremia in humans can cause spontaneous and stimulus-sensitive myoclonus that responds to clonazepam. Uremic myoclonus in humans resembles the reticular reflex form of postanoxic action myoclonus. Previous investigations have established that urea infusions in the cat can produce spontaneous and stimulus-sensitive myoclonus. This has been shown, electrophysiologically, to arise in the brainstem medullary reticular formation, and it does not require forebrain structures. Our own studies in the rat have shown that urea infusions also produce spontaneous and stimulus-sensitive myoclonus. Electrophysiologically, this resembles human reticular reflex myoclonus. It can be reduced by clonazepam. The myoclonus produced by urea infusions in the rat progresses very rapidly into uncontrollable tonic-clonic convulsions. Although the urea model in the rat mimics some forms of human myoclonus that arise in the brainstem, it is not suitable as a routine animal model for pharmacological investigations.
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PMID:Urea-induced stimulus-sensitive myoclonus in the rat. 394 17

We describe a patient with epilepsy characterized by eyelid myoclonus, which often evolved into complex partial seizures, hemiconvulsions, or generalized convulsions. The outstanding feature was that seizures became markedly more frequent on exposure to light, movement in daily life, and hot water immersion. The patient was highly susceptible to seizures under constant light, but the dopamine level in the cerebrospinal fluid was quite low, and administration of levodopa transiently suppressed the seizures.
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PMID:Epileptic seizures precipitated by constant light, movement in daily life, and hot water immersion. 400 84

The onset pressures for the tremor, myoclonus and convulsions seen in the high pressure neurological syndrome (HPNS) are increased following cis-2,3-piperidine dicarboxylic acid 1 mmol/kg in the rat. Glutamic acid diethyl ester 1-3 mmol/kg has no effect on tremor or myoclonus, but increases the convulsion pressure when 3 mmol/kg is given immediately before compression. These and earlier data with 2-amino-7-phosphonoheptanoic acid suggest that excitation at the N-methyl-D-aspartate receptor is important in HPNS tremor, and that excitation at the quisqualate receptor contributes to HPNS convulsions.
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PMID:Effect of excitatory amino acid antagonists on the high pressure neurological syndrome in rats. 609 58

1 The effect of catechol on uptake and K+-stimulated release of gamma-aminobutyric acid (GABA), D-aspartate, noradrenaline and acetylcholine has been studied in slices of cerebral cortex and thalamus. 2 Low concentrations of catechol did not influence the uptake of any of the neurotransmitters in either brain area. 3 Noradrenaline release was unaffected by catechol. 4 Acetylcholine release from both cortical and thalamic slices was inhibited by high concentrations of catechol. This phenomenon is unlikely to be related to catechol-induced convulsions. 5 Catechol (100 microM) inhibited GABA release from cortical slices by 28%. However, at a concentration of 10 microM catechol enhanced the release of D-aspartate from thalamic slices by over 100%. 6 Potentiated release of excitatory amino acid transmitters may contribute to the enhanced excitability of thalamic cells which occurs during sensory myoclonus induced by low doses of catechol.
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PMID:The effect of the convulsant agent, catechol, on neurotransmitter uptake and release in rat brain slices. 611 45

The elevated atmospheric pressure at which the main features of the high pressure neurological syndrome (HPNS), i.e. tremor, myoclonus and convulsions, successively appear, have been studied in fed and fasted rats with and without pretreatment with 2-amino-7-phosphonoheptanoic acid (180 mg/kg). The onset pressure for tremor is lower in fasted rats. 2-Amino-7-phosphonoheptanoic acid raises the onset pressure for all three phases of HPNS in fed rats, but only for tremor and convulsions in fasted rats. The results are interpreted in terms of changes in aspartergic and related excitatory neurotransmission.
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PMID:The high pressure neurological syndrome and 2-amino-7-phosphonoheptanoic acid: differences between fed and fasted rats. 614 24

The binding of [3H] diazepam and [3H] flunitrazepam in rat cerebral cortex was not altered by either acute or chronic administration of pentylenetetrazol except in rats made to convulse 30 min before sacrifice. Rats treated for up to 6 months with doses of pentylenetetrazol which are below seizure threshold in naive rats, became increasingly sensitive to the CNS stimulant effect of pentylenetetrazol as demonstrated by the development of myoclonus and convulsions during treatment periods. These effects were not correlated with any changes in benzodiazepine binding in cerebral cortex or cerebellum and [3H] quinuclidinyl benzilate binding in cerebral cortex. Acute convulsant doses of pentylenetetrazol increased benzodiazepine binding in cerebral cortex, but only in those rats which actively convulsed. Benzodiazepine and cholinergic receptors of the cortex, and benzodiazepine receptors of the cerebellum, therefore, do not appear to change with either the acute or chronic subconvulsive administration of pentylenetetrazol.
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PMID:Effect of acute and chronic pentylenetetrazol treatment on benzodiazepine and cholinergic receptor binding in rat brain. 627 62

We reported a case of late infantile neuronal ceroid-lipofuscinosis. The patient was an 8-year-old boy presenting with marked psychomotor deterioration, progressive visual failure due to retinal degeneration and optic atrophy, startle reaction to auditory stimuli, frequent myoclonus and generalized convulsions. The routine laboratory examinations were all normal. EEG was markedly abnormal because of poorly organized background activity and frequent paroxysmal spike-and-wave complexes. CT scan showed evidence of severe atrophy of the cerebrum, cerebellum and brainstem. Electron microscopic examination of the biopsied rectum revealed fingerprint profiles in the neurons and pericytes beneath the muscularis mucosa. Cultured skin fibroblasts also contained electron dense inclusions, some of which showed fingerprint profiles. Urinary glycopeptides were normal. Lyscsomal enzyme activities in leukocytes and cultured fibroblasts were normal. Neurophysiological studies revealed giant cortical potentials evoked by the auditory as well as somatosensory stimulation. Simultaneous recording of the somatosensory evoked EEG and EMG potentials disclosed that the myoclonus in this patient was stimulus-sensitive and compatible with the cortical reflex myoclonus. With regard to hypothetical pathogenesis of this disease, we studied lipoperoxide in the blood before and after anti-oxidant therapy. We also measured vitamin A and carotene, since these substrates are related to retinoic acid. Although vitamin A and carotene were normal, lipoperoxide was slightly elevated. However, it was not influenced by the treatment with anti-oxidant. Significance of elevated lipoperoxide to the pathogenesis of this diseases has not solved.
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PMID:[A case of neuronal ceroid-lipofuscinosis (Jansky-Bielshowsky type): morphological, biochemical and electrophysiological studies (author's transl)]. 627 66

An autopsy case of a Japanese male with familial beta-galactosidase and neuraminidase deficiency is reported. The clinical picture was characterized by adult onset, a gargoyle-like face, cerebellar ataxia, myoclonus, convulsions, retinal degeneration and cortical blindness. Histopathologically, most neurons seemed to have become degenerated in the whole cerebral cortex. Moreover, the calcarine cortex appeared spongy with depopulation of nerve cells. Stuffed neurons or neuronal storage changes were found throughout the brain, especially in the motor nuclei of the spinal cord and brain stem. The inclusions in the stuffed neurons revealed various profiles on the electron microscope. They were composed of membranous lamellar and/or multilamellar structures, often accompanying vacuoles and reminiscent of lipofuscin-like profiles.
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PMID:Neuropathological findings of an autopsy case of adult beta-galactosidase and neuraminidase deficiency. 631 9

Positron emission tomography (PET) with fluorine-18-labeled fluorodeoxyglucose (18FDG) has demonstrated the epileptogenic lesion in partial epilepsy to be hypometabolic interictally . This finding is useful for localizing the area of resection when surgical therapy is contemplated. 18FDG scans during partial seizures show increased metabolism in areas of ictal onset and spread and in other regions of decreased metabolism that could reflect postictal effects. In the generalized epilepsies, petit mal absences and generalized convulsions induced by electroconvulsive shock therapy (ECT) are associated with global hypermetabolism, while global hypometabolism is seen in the postictal period following ECT. More information about the factors that influence the interictal hypometabolic zone in partial epilepsy should improve the diagnostic value of this finding for presurgical localization and perhaps also for the evaluation of other therapeutic regimens. New techniques for more dynamic PET studies with improved resolution, combined with computerized electroencephalographic analysis, should allow more accurate interpretation of ictal, as well as interictal, phenomena. Application of PET technology to other paroxysmal disorders may provide a basis for new diagnostic classifications that have therapeutic and prognostic value and may allow clearer differentiation among epileptic phenomena, myoclonus, and movement disorders. More clinical and animal research is needed, however, before we can delineate fundamental mechanisms of human epilepsy from PET data. To this end, it is now possible to use combined multidisciplinary parallel approaches in patients and animals to define specific aspects of epileptic disorders clinically, to intensively investigate them with experimental models in the animal laboratory, and to verify the relevance of these experimental results by returning to clinical studies.
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PMID:The use of positron emission tomographic scanning in epilepsy. 643 Feb 15


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