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)

Inherited congenital myoclonus (ICM) of Poll Hereford cattle is a neurological disease in which there are severe alterations in spinal cord glycine-mediated neurotransmission. There is a specific and marked decrease, or defect, in glycine receptors and a significant increase in neuronal (synaptosomal) glycine uptake. Here we have examined the characteristics of the cerebral gamma-aminobutyric acid (GABA) receptor complex, and demonstrate that the malfunction of the spinal cord inhibitory system is accompanied by a change in the major inhibitory system in the cerebral cortex. In synaptic membrane preparations from ICM calves, both high-and low-affinity binding sites for the GABA agonist [3H]muscimol were found (KD = 9.3 +/- 1.5 and 227 +/- 41 nM, respectively), whereas only the high-affinity site was detectable in controls (KD = 14.0 +/- 3.1 nM). The density and affinity of benzodiazepine agonist binding sites labelled by [3H]diazepam were unchanged, but there was an increase in GABA-stimulated benzodiazepine binding. The affinity for t-[3H]butylbicyclo-o-benzoate, a ligand that binds to the GABA-activated chloride channel, was significantly increased in ICM brain membranes (KD = 148 +/- 14 nM) compared with controls (KD = 245 +/- 33 nM). Muscimol-stimulated 36Cl- uptake was 12% greater in microsacs prepared from ICM calf cerebral cortex, and the uptake was more sensitive to block by the GABA antagonist picrotoxin. The results show that the characteristics of the GABA receptor complex in ICM calf cortex differ from those in cortex from unaffected calves, a difference that is particularly apparent for the low-affinity, physiologically relevant GABA receptors.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Increased gamma-aminobutyric acid receptor function in the cerebral cortex of myoclonic calves with an hereditary deficit in glycine/strychnine receptors. 216 65

It has been hypothesized that the Long-Sleep and Short-Sleep mouse lines were bidirectionally selected for high and low brain excitability, and further, that these differences are mediated by the benzodiazepine/gamma-aminobutyric acid (GABA) receptor-chloride channel complex. Hence, mice from both lines were administered seven convulsants (bicuculline, pentylenetetrazol, 3-carbomethoxy-beta-carboline, picrotoxin, caffeine, flurothyl and strychnine) and myoclonic and clonic seizure latencies recorded. Supporting the original hypothesis, the results show that the two lines were differentiated by all of the convulsants and that in response to the drugs, three distinct convulsive patterns were found. Nevertheless, a simple genetic model accounting for these results was not evident. To further clarify these susceptibility patterns, a convulsant representing each of these patterns (bicuculline, pentylenetetrazol or caffeine) was administered in conjunction with the anticonvulsant-barbiturate phenobarbital or the benzodiazepine antagonist Ro 15-1788. Irrespective of the convulsant given, phenobarbital attenuated both myoclonus and clonus subsequent to all convulsants, while Ro 15-1788 had a more discrete anticonvulsant profile.
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PMID:Patterns of convulsive susceptibility in the long-sleep and short-sleep selected mouse lines. 250 42

A 66-year-old male receiving intravenous piperacillin and nafcillin for a post-surgical wound infection developed intermittent myoclonic jerks of all four extremities that disappeared after discontinuation of these two medications. In addition there was a mild yet definite intermittent encephalopathic effect; head computed tomography examination as negative and there was no prior history for seizure or myoclonus. These two beta lactam ring antibiotics are structurally similar to penicillin, which is well known to induce not only myoclonus but also seizure activity by reducing the gamma-aminobutyric acid (GABA) induced inhibitory currents by inducing an open chloride channel block of the GABA type A receptors within the brain. Clinicians need to be fully aware of the potential epileptogenic effects of piperacillin, nafcillin, and related antibiotics.
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PMID:Myoclonic jerks secondary to piperacillin and nafcillin. 2498 1