Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004134 (ataxia)
 15,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ralitoline, a thiazolidinone derivative chemically distinct from known antiepileptic drugs, possesses remarkable anticonvulsant properties as demonstrated in various animal models of epilepsy. The efficacy of this compound seems to be comparable or even better than that of conventional antiepileptics. In the present study, the activity of ralitoline was investigated in four seizure models in rodents in order to characterize the anticonvulsant profile of action further. In the maximal electroshock seizure test (mice), this compound showed marked anticonvulsant effects (ED50 2.8 mg/kg i.p.). The efficacy of clinically established anti-epileptics was significantly increased when ralitoline was given as co-medication. In the strychnine seizure test (mice), ralitoline (5 and 10 mg/kg) prolonged the latency of tonic seizures as well as the survival time. On the other hand, in the subcutaneous pentylenetetrazol seizure threshold test (mice), this drug revealed limited protective actions at higher doses and increased the effectiveness of ethosuximide. In unrestrained rats with chronically implanted electrodes, ralitoline (5 mg/kg) significantly reduced the duration of electrically-evoked hippocampal discharges and raised the focal stimulation threshold (10 mg/kg). In the rotorod ataxia test (mice), a TD50 value of 14.5 mg/kg i.p. was determined for ralitoline (protective index TD50/MES-ED50 5.2). With regard to the possible mode of action, whole-cell voltage-clamp experiments on cultured neonatal rat cardiomyocytes showed that ralitoline may act specifically on voltage-sensitive sodium channels. The compound inhibited the fast sodium inward current in a frequency- and voltage-dependent manner. In conclusion, the findings confirm the potent anticonvulsant effects of ralitoline, especially against generalized tonic-clonic and complex partial seizures. Moreover, in combination with antiepileptics, an additive synergism can be found at lower concentrations. Regarding the mode of action, this drug was capable of depressing the fast sodium inward current in cultured heart ventricular cells, suggesting that the local anesthetic properties may be important for the anticonvulsant activity of ralitoline.
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PMID:Anticonvulsant and sodium channel blocking effects of ralitoline in different screening models. 133 17

Pioneering studies in our laboratories have led to the emergence of the delta 2-1,2,3-triazolines (4,5-dihydro-1H-1,2,3-triazoles) and the closely related 1H-1,2,3-triazoles as a unique family of anticonvulsant agents hitherto unknown. Unlike the traditional anticonvulsants, the dicarboximide moiety is absent from the traiazoline ring system. This paper examines the results of evaluation of several groups of 1-aryl-5-pyridyl-substituted triazolines and triazoles with particular reference to structure-activity relationships in each compound group as well as between compounds in the different groups and the 1,5-diaryl compounds. The Topliss manual approach for application fo the Hansch method is employed for the rational design of triazoline/triazole anticonvulsants. Anticonvulsant activity was determined, after intraperitoneal administration, in two standard seizure models in the mouse, the MES and scMet tests. Central nervous system toxicity was evaluated in the rotorod ataxia test. Analysis of structure-activity relationships using the Topliss scheme indicated a clear pi + sigma dependency in the 1-aryl-5-(4-pyridyl)triazolines while an adverse steric effect (Es) from 4-substitution appeared to be present in the 1-aryl-5-(3-pyridyl) compounds. A similar but strong steric effect dominated the structure-activity pattern of the 1-aryl-5-(4-pyridyl)triazoles, although a sigma dependency was more evident in the 1-aryl-5-(3-pyridyl)- and the 1,5-diaryltriazole series. No significant activity was observed among the 1-aryl-5-(2-pyridyl)triazolines, and although the respective triazoles were active, the parameter dependency was not clearly defined. Similarly, the 1,5-diaryltriazolines, as a group, showed no pronounced anticonvulsant activity. However, replacement of the 5-aryl with a pyridyl group, particularly a 4-pyridyl, led to highly enhanced anticonvulsant activity. In addition, oxidation of triazolines with no anticonvulsant activity yielded, as a rule, triazoles that were active, which could be linked to their chemistry or structural conformation. The triazolines and triazoles evince anticonvulsant activity as a class and compare very well with the prototype antiepileptic drugs--ethosuximide, phenytoin, phenobarbital, valproate--in their anticonvulsant potency and minimal neurotoxicity. They have emerged as a new generation of anticonvulsant agents that show great promise as potentially useful antiepileptic drugs.
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PMID:Triazolines. 14. 1,2,3-Triazolines and triazoles, a new class of anticonvulsants. Drug design and structure-activity relationships. 333 19

1. GYKI 52466 is a benzodiazepine derivative that has muscle relaxant and anticonvulsant properties thought to be mediated by highly selective, noncompetitive antagonism of non-NMDA receptors. However, recent electrophysiological data showed that, in addition to non-NMDA receptors, the GABAA-receptor associated benzodiazepine site is involved in the depressant effect of GYKI 52466 on spinal reflex transmission. In view of the structural similarities between the 2,3 benzodiazepine derivative GYKI 52466 and 1,4-benzodiazepines such as diazepam, the benzodiazepine site of GABAA receptor complex could also be involved in the anticonvulsant activity of GYKI 52466, which has not yet been proven. This prompted us to study the effect of the benzodiazepine receptor antagonist, flumazenil, on anticonvulsant and adverse effects of GYKI 52466 in different seizure models in mice. The non-NMDA antagonist, NBQX and diazepam were used for comparison. 2. Seizure threshold models for different types of generalized seizures were used. The threshold for maximal (tonic) electroshock seizures (MES) was significantly increased by GYKI 52466 (10-20 mg kg-1), NBQX (80-120 mg kg-1) and diazepam (5 mg kg-1) shortly after i.p. drug administration. The same dose-range of the non-NMDA antagonists also significantly increased the threshold for myoclonic and clonic seizures induced by i.v. infusion of pentylenetetrazol (PTZ), although the magnitude of threshold increases obtained with the respective drugs, differed, at least in part, from that seen in the MES experiments. GYKI 52466 was clearly less potent in increasing PTZ thresholds for myoclonic and clonic seizures than on the MES threshold, while NBQX exerted about the same potency in both models. In contrast to the non-NMDA antagonists, diazepam was capable of increasing themyoclonic and clonic PTZ seizure threshold at much lower doses than the MES threshold. The PTZ threshold for tonic seizures was markedly increased by GYKI 52466, while NBQX and diazepam were clearly less potent in this respect.3. With respect to adverse effects, GYKI 52466 and NBQX induced significant seizure threshold increases in the different seizure models only at doses which caused sedation and ataxia, while diazepam increased the myoclonic and clonic PTZ seizure threshold at doses below those inducing motor impairment.4. Flumazenil (5-20 mg kg-1) antagonized the anticonvulsant and adverse effects of diazepam but not GYKI 52466. Instead, the anticonvulsant effect of GYKI 52466 was potentiated by flumazenil in some experiments. The anticonvulsant activity of NBQX was slightly reduced by flumazenil in the MES model but not in the PTZ test.5. The data indicate that the GABAA receptor-associated benzodiazepine site is not critically involved in anticonvulsant or adverse effects of GYKI 52466. However, both GYKI 52466 and NBQX were unable to increase seizure thresholds at doses below those inducing sedation and motor impairment,thus demonstrating that non-NMDA antagonists lack a selective anticonvulsant action in standard models of generalized seizures.
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PMID:Effects of the non-NMDA antagonists NBQX and the 2,3-benzodiazepine GYKI 52466 on different seizure types in mice: comparison with diazepam and interactions with flumazenil. 788 91