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)

An abnormality of serotonergic neurotransmission has been hypothesized in p,p'-DDT intoxication to explain myoclonus and the antimyoclonic properties of 5-hydroxytryptophan (5-HTP). To study the role of serotonin (5-HT) receptors in myoclonus induced by p,p'-DDT in the rat, we performed time-course and dose-response studies of the effects of p,p'-DDT on behavior and regional 5-HT1 and 5-HT2 binding sites. At a time when low dose (80 mg/kg) p,p'-DDT elicited stimulus-sensitive and spontaneous myoclonus, there were no significant changes in Bmax or Kd of 5-HT1A, 5-HT1B, 5-HT1C sites in cortex, striatum, brainstem or spinal cord, agonist- or antagonist-labelled 5-HT2 sites in cortex, or 5-HT uptake sites. High dose p,p'-DDT (1000 but not 500 mg/kg), which also induced convulsions, only slightly increased 5-HT1 (unsubtyped) binding sites in cortex but not in brainstem or spinal cord and had no effect on antagonist-labelled 5-HT2 sites. In naive frontal cortex in vitro, 1 microM p,p'-DDT displaced neither [3H]5-HT or [3H]ketanserin specific binding. Lesions of central indoleamine neurons made with 5,7-dihydroxytryptamine significantly prolonged the latency and attenuated the severity of p,p'-DDT behavioral abnormalities, increasing the dose of p,p'-DDT which induced myoclonus (MD50) or convulsions (CD50) in 50 percent of the rats. This is the first report of 5,7-DHT-induced attenuation in the p,p'-DDT myoclonic model.
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PMID:p,p'-DDT myoclonic/epileptic model: serotonin receptor binding and behavioral studies in the rat. 799 Dec 14

We confirmed that the effects of inhibitors of nitric oxide (NO) synthase, such as Nomega-nitro-L-arginine methyl ester and Nomega-nitro-L-arginine, differ depending on several experimental factors. Both compounds but not their less active enantiomers delayed picrotoxin-induced clonus in mice yet increased the incidence of clonus following low-dose picrotoxin. Nomega-nitro-L-arginine methyl ester significantly reduced the latencies of both myoclonus and clonus in older but not younger Sprague-Dawley rats receiving pentylenetetrazol s.c. By contrast, there was no significant change in the latencies for myoclonus and clonus in Wistar rats (older and younger). However, when pentylenetetrazol was administered i.p. rather than s.c., Nomega-nitro-L-arginine methyl ester dramatically increased latencies of convulsive indicators, including tonus, in both Sprague-Dawley and Wistar rats. Nomega-nitro-L-arginine methyl ester also delayed tonus but not myoclonus or clonus in mice, regardless of the systemic route of administration of pentylenetetrazol. Both Nomega-nitro-L-arginine methyl ester and NG-nitro-L-arginine increased the tonic CD50 of pentylenetetrazol in mice and Nomega-nitro-L-arginine methyl ester delayed 4-aminopyridine-induced tonus. However, Nomega-nitro-L-arginine methyl ester reduced the tonic CD50 of both picrotoxin and 4-aminopyridine in mice and failed to suppress tonus following maximal electroshock. Evidently, inhibitors of NO synthase are not universally effective antitonic drugs.
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PMID:Further studies on anti- and proconvulsant effects of inhibitors of nitric oxide synthase in rodents. 957 Apr 42