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L Velísek

Publications and source records attributed to L Velísek.

61 records · Page 4Linked to original sources
PubMed1986

Influence of ethosuximide and dipropylacetate on metrazol-induced electrocorticographic changes during ontogenesis in rats.

Influence of ethosuximide (ESI, 125 mg/kg i.p.) and dipropylacetate (DPA, 300 mg/kg i.p.) pretreatment on electrocorticographic changes induced by pentamethylenetetrazole (PTZ, 20 mg/kg dose every 5 min) was studied in rats aged 7, 12, 18 and 90 days. PTZ alone induced isolated spikes and/or sharp waves as the first sign of its action in all age groups except in adult animals where rhythmic theta activity was elicited. The antiepileptic effect of DPA was observed in 12- and 18-day-old rats, ESI specifically inhibited rhythmic activity in adult rats. ECoG seizures induced by high doses of PTZ were inhibited by DPA in all age groups, ESI tended to be effective in adult rats only. DPA did not change the pattern of ECoG seizures, whereas ESI led to replacement of the spike-and-wave rhythm by serrated waves in adult animals. The low ability of immature brain to generalize ictal activity was further diminished by ESI.

Animals↗
PubMed1984

Effect of anticonvulsant drugs on thalamo-cortical and hippocampo-cortical self-sustained after-discharges in the rat.

The action of four antiepileptic drugs was studied in acute experiments in 98 rats. Two types of cortical self-sustained afterdischarges ( SSADs ) induced by rhythmic electrical stimulation of subcortical structures were used as models. SSAD formed by the spike-and-wave rhythm (most frequently induced by stimulation of thalamic somatosensory relay nucleus) was almost completely blocked by dipropylacetate (valproate, 400 mg/kg i.p.) and significantly shortened by ethosuximide (125 mg/kg i.p.). Diphenylhydantoin (60 mg/kg i.p.) tended to prolong this type of SSAD whereas carbamazepine did not influence it. SSAD formed by serrated waves (induced usually by stimulation of the dorsal hippocampus) was augmented by ethosuximide, uninfluenced by dipropylacetate and diphenylhydantoin, and significantly shortened by carbamazepine. The pharmacological profile of the two types of SSADs is in agreement with our hypothesis that the spike-and-wave type of SSAD represents a model of primary generalized seizures of the absence type whereas hippocampo -cortical SSAD could be used as a model of partial seizures with complex symptomatology.

Animals↗
PubMed1983

Influence of ethosuximide on metrazol-induced seizures during ontogenesis in rats.

Effects of metrazol (pentylenetetrazole and ethosuximide were studied in male albino rats aged 7, 12, 18 and 90 days. The 18-day-old rats exhibited the highest sensitivity to metrazol. CD50s in the remaining three age groups were nearly the same. Ethosuximide was reliably effective against metrazol only in adult rats; in young animals it did not significantly change CD50s. Metrazol induced in ethosuximide-pretreated young rats either modified (long-lasting minimal seizures in 18-day-old animals) or new seizure patterns (minimal seizures in 7- and 12-day-old rats).

Aging↗
PubMedDate not supplied

Developmental seizure models.

Seizures frequently occur in children. There are significant differences in the generation, expression and modification of seizures as a function of age. Animal models of epilepsy should depict these age-related differences. In this paper, we summarize the main features of generalized flurothyl, pentylenetetrazol, bicuculline and picrotoxin-induced seizures in adult and immature rats as well as the characteristics of focal seizures induced by amygdala kindling, systemic NMDA and kainic acid. Some of the models may be more advantageous for screening antiepileptic drug effects whereas other models may be more helpful in studying the basic mechanisms of epilepsy.

Animals↗
PubMedDate not supplied

Action of antiepileptic drugs against kainic acid-induced seizures and automatisms during ontogenesis in rats.

Kainic acid (KA 4-14 mg/kg) administered intraperitoneally (i.p.) produces automatisms (scratching until third postnatal week, "wet dog" shakes thereafter), and clonic and tonic-clonic seizures in rats aged 7, 12, 18, 25, and 90 days. Administration of carbamazepine (CBZ) i.p. (25 or 50 mg/kg), phenobarbital (PB 20-80 mg/kg), clonazepam (CZP 0.2 or 1 mg/kg), or valproate (VPA 200 mg/kg) influenced neither incidence nor latency of automatisms. Clonic seizures that are regularly observed after the third postnatal week in controls were either abolished or substantially suppressed by any of the aforementioned antiepileptic drugs (AEDs). Tonic-clonic seizures observed in the first 3 postnatal weeks were suppressed only by solvent [including propyleneglycol (PEG), ethanol, and water]; the effect of AEDs on tonic-clonic seizures was proconvulsant instead. The automatisms were most resistant to AED therapy. These results induce some doubts about the adequacy of the KA model for identifying AEDs effective against complex partial seizures, but forthcoming AEDs that suppress automatisms in the KA rat model might also be active against human complex partial seizures.

Animals↗
PubMedDate not supplied

Effects of a benzodiazepine, bretazenil (Ro 16-6028), on rhythmic metrazol EEG activity: comparison with standard anticonvulsants.

A novel anticonvulsant benzodiazepine bretazenil (Ro 16-6028) was studied electrophysiologically in a model of human absence seizures: rhythmic metrazol activity (RMA) in rats. The effects of Ro 16-6028 pretreatment (0.01, 0.05, or 0.1 mg/kg intraperitoneally, i.p.) were compared with those of clonazepam (CZP, 0.02 or 0.1 mg/kg i.p.), valproate (VPA, 200, 300, or 400 mg/kg) and ethosuximide (ESM, 31.25, 62.5, or 125 mg/kg i.p.) in 45 rats with implanted electrocorticographic electrodes. RMA was elicited by an injection of pentylenetetrazol (metrazol, PTZ) in a dose of 40 or 35 mg/kg i.p. The effects of Ro 16-6028 were similar to those of CZP and VPA, i.e., suppression of RMA episodes, an increase in latency and a decrease in number, and total as well as mean duration. On the other hand, ESM differed from these antiepileptic drugs (AEDs) in inability to shorten the duration of RMA episodes. Based on these results, Ro 16-6028 might be predicted to be efficient against human absence seizures.

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