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12. Models of epileptic seizures in immature rats

Creator:
Pavel Mareš
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, rat, ontogeny, epileptic seizures, convulsant drugs, electrical stimulation, 14, and 612
Language:
English
Description:
Models of basic types of epileptic seizures are elaborated not only in adult but also in immature rodents. It is important because at least half of human epilepsies starts during infancy and childhood. This paper presents a review of chemically and electrically induced models of generalized convulsive and nonconvulsive (absence) seizures as well as models of partial simple (neocortical) and complex (limbic) seizures in immature rats. These models can also serve as a tool for study the development of central nervous system and motor abilities because the level of maturation is reflected in seizure semiology. Age-dependent models of epileptic seizures (absences and flexion seizures) are discussed. Models of seizures in immature animals should be used for testing of potential antiepileptic drugs., P. Mareš., and Obsahuje seznam literaury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

13. NMDA and AMPA receptors: development and status epilepticus

Creator:
Szczurowska, E. and Pavel Mareš
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, mozek, mutace (biologie), epilepsie, brain, mutation (biology), epilepsy, glutamate receptors, 14, and 612
Language:
English
Description:
Glutamate is the main excitatory neurotransmitter in the brain and ionotropic glutamate receptors mediate the majority of excitatory neurotransmission (Dingeldine et al. 1999). The high level of glutamatergic excitation allows the neonatal brain (the 2 nd postnatal week in rat) to develop quickly but it also makes it highly prone to age-specific seizures that can cause lifelong neurological and cognit ive disability (Haut et al. 2004). There are three types of ionotropic glutamate receptors (ligand-gated ion channels) named according to their prototypic agonists: N- methyl-D-aspartate (NMDA), 2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl) propanoic acid (AMPA) and kainate (KA). During early stages of postnatal development glutamate receptors of NMDA and AMPA type undergo intensive functional changes owing to modifications in their subunit composition (Carter et al. 1988, Watanabe et al. 1992, Monyer et al. 1994, Wenzel et al. 1997, Sun et al. 1998, Lilliu et al. 2001, Kumar et al. 2002, Matsuda et al. 2002, Wee et al. 2008, Henson et al. 2010, Pachernegg et al. 2012, Paoletti et al. 2013). Participation and role of these receptors in mechanisms of seizures and epilepsy became one of the main targets of intensive investigation (De Sarro et al. 2005, Di Maio et al. 2012, Rektor 2013). LiCl/Pilocarpine (LiCl/Pilo) induced status epilepticus is a model of severe seizures resulting in development temporal lobe epilepsy (TLE). This review will consider developmental changes and contribution of NMDA and AMPA receptors in LiCl/Pilo model of status epilepticus in immature rats., E. Szczurowska, P. Mareš., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

14. Ontogenetic development of sensitivity of the cerebral cortex to an Antagonist of GABAA receptor bicuculline

Creator:
Pavel Mareš, Klára Bernášková, and Hana Kubová
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fyziologie člověka, human physiology, Cerebral cortex, Rat, Postnatal development, Epileptic phenomena, Bicuculline, 14, and 612
Language:
English
Description:
Local application of four concentrations of bicuculline methiodide (a specific antagonist of GABAA receptors) was used to study a sensitivity of somatosensory cortex in four age groups of immature rats with implanted electrodes. Presence and latencies of two epileptic phenomena (focal discharges and seizures) were evaluated. Focal discharges exhibited moderate tendency to a decrease of sensitivity to bicuculline methiodide with maturation. Concentration-effect relation of incidence of focal discharges was observed only in 7- and 12-day-old but not in older animals. Results with incidence and latencies of seizures did not show relations to age or concentration of bicuculline. Neither of the epileptic phenomena can be used as a reliable index of cortical maturation., P. Mareš, K. Bernášková, H. Kubová., and Seznam literatury
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

15. Partial agonist of benzodiazepine receptors ro 19-2088 elicits withdrawal symptoms after short-term administration in immature rats

Creator:
Hana Kubová and Pavel Mareš
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, Ro 19-2088, iatrogenic withdrawal, pentylentetrazol-induced seizures, immature rats, 14, and 612
Language:
English
Description:
Repeated administration of partial agonist of benzodiazepine receptors Ro 19-8022 (a derivative of quinolizine class) does not elicit withdrawal in adult rats. Our older data demonstrated that single injection of Ro 19-2088 to immature rats induces increased sensitivity to convulsant action of pentylenetetrazol as a withdrawal phenomenon. To know if repeated administration of the partial agonist has the same effect we injected rats at postnatal days 7 to 11 with an anticonvulsant dose of Ro 19-2088 (0.5 mg/kg i.p.) and tested them 24 h, 48 h and 4 days after the last injection. Repeated administration of Ro 19-8022 resulted also in an increased sensitivity to convulsant action of pentylenetetrazol in immature rats (higher incidence and severity of seizures). This effect was significant 24 h after the last injection but only outlined 48 h after administration. No signs of hypersensitivity were seen at 4-day interval. There is a difference between immature and adult brain in an appearance of withdrawal symptom after administration of the partial agonist of benzodiazepine receptors Ro 19-2088., H. Kubová, P. Mareš., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

16. Positive allosteric modulator of mGluR4 PHCCC exhibits proconvulsant action in three models of epileptic seizures in immature rats

Creator:
Szczurowska, E. and Pavel Mareš
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, metabotropic glutamate receptor 4, epileptic seizures, rat, ontogeny, 14, and 612
Language:
English
Description:
The activation of metabotropic glutamate receptors subtype 4 (mGluR4) potentiates models of absence seizures in adult rats. These seizures are age-dependent, but data concerning the role of mGluR4 in immature brain is insufficient. N-phenyl-7- (hydroxyimino)cyclopropa[b]chromen-1acarboxamide (PHCCC), which is a positive allosteric modulator of these receptors, was used in three different models of seizures in immature rats: 1) convulsions induced by high doses of pentetrazol (PTZ; a model of generalised tonic-clonic seizures); 2) rhythmic electroencephalographic (EEG) activity induced by low doses of PTZ (a model of absence seizures); and 3) electrically elicited cortical afterdischarges (ADs, a model of myoclonic seizures). We administered four doses of PHCCC (1, 3, 10 and 20 mg/kg) in PTZ-induced convulsions and two doses (3 and 10 mg/kg) in the two electrophysiological models of freely moving rats with implanted electrodes. Every dose and age group consisted from 8 to 10 rats. PTZ-elicited convulsions were not significantly influenced by PHCCC. In contrast, PHCCC potentiated the effect of a subconvulsant dose (60 mg/kg) of PTZ. The 10-mg/kg dose of PHCCC significantly prolonged the duration of PTZ-induced rhythmic activity episodes and shortened the intervals between individual episodes in 25-day-old rats (P25). In contrast, this potentiation was not seen in P18 rats. Cortical ADs were significantly prolonged with repeated stimulations by both doses of PHCCC in P12 and P18 animals. P25 rats exhibited only slightly longer AD durations. In conclusion, we did not find any anticonvulsant effect of PHCCC. On the contrary, proconvulsant action was demonstrated in all three models in immature rats., E. Szczurowska, P. Mareš., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

17. Proconvulsant action of two GABAb receptor antagonists is age-dependent

Creator:
Pavel Mareš
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, elektroencefalogramy, electroencephalograms, GABAb receptor antagonists, cortical afterdischarges, immature rats, 14, and 612
Language:
English
Description:
Antagonists of GABA B receptors are expected to have proconvulsant acti on also in developing brain. Two antagonists (CGP55845 and CGP46381) were tested in a model of cortical epileptic afterdischarges (ADs) in 12-, 18- and 25-day-old rat pups with implanted electrodes. CGP55845 was dissolved in dimethylsulfoxide and the results demonstrated marked proconvulsant action of this solvent which masked possible action of the antagonist. Water soluble antagonist CGP46381 led to marked potentiation of ADs in 12-day-old animals, its action decreased with age, it was negligible in 25-day-old rats. Our results demonstrated important inhibitory role of GABA B receptors at very early stages of maturation., P. Mareš., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

18. Similar effects of lamotrigine and phenytoin against cortical epileptic foci in immature rats

Creator:
Klára Bernášková and Pavel Mareš
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, mozková kůra, cerebral cortex, epileptic focus, bicuculline methiodide, immature rat, antiepileptic drugs, 14, and 612
Language:
English
Description:
Action of antiepileptic drugs in immature brain may differ from that in adult brain. The aim of our study was to study an anticonvulsant action of lamotrigine and phenytoin, i.e. two drugs active against partial seizures in adult experimental animals as well as human patients, in a model of simple partial seizures in immature rats. Epileptic foci were induced by local application of bicuculline methiodide on sensorimotor cortical area of 12-dayold rat pups. The animals were pretreated with lamotrigine (LTG, 10 or 20 mg/kg i.p.) or phenytoin (PHT, 15, 30 or 60 mg/kg i.p.). Control rats for LTG received saline, controls for PHT solvent composed of propyleneglycol, ethanol and water. Influence of either drug on interictal activity was negligible. High doses of both LTG and PHT suppressed the transition into ictal phases and shortened the duration of persisting seizures. The tricomponent solvent exhibited moderate activity against ictal activity if compared with saline controls. The two drugs exhibited similar action in our model, i.e. the suppression of secondary generalization from epileptic focus. This action is comparable to that described for human patients and adult experimental animals. In favor of lamotrigine speaks the absence of serious side effects., K. Bernášková, P. Mareš., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

19. Transient changes of cortical interhemispheric responses after repeated caffeine administration in immature rats

Creator:
Tchekalarova, J., Hana Kubová, and Pavel Mareš
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, evokované potenciály, mozková kůra, kofein, evoked potentials, cerebral cortex, caffeine, development, rat, 14, and 612
Language:
English
Description:
Repeated postnatal caffeine treatment of rat pups led to transient developmental changes in cortical epileptic afterdischarges. To know if physiological cortical functions are also affected transcallosal evoked potentials were studied. Rat pups of the Wistar strain were injected daily with caffeine (10 or 20 mg/kg s.c.) from postnatal day (P) 7 to P11, control siblings received saline. Cortical interhemispheric responses were tested at P12, 18, 25 and in young adult rats. Amplitude of initial monosynaptic components was evaluated in averaged responses. Single pulses as well as paired and frequency (five pulses) stimulations were used. Developmental rules - highest amplitude of responses in 25-day-old rats, potentiation with paired and frequency stimulation present since P18 - were confirmed. Caffeine-treated rats exhibited transient changes: single responses were augmented in P25 if high stimulation intensity was used, paired-pulse and freque ncy responses were higher in experimental than in control anim als at P12, the opposite change was observed in 18- and more ma rkedly in 25-day-old rats. No significant changes were found in adult animals, monosynaptic transcallosal responses represent a simple and robust system. The developmental profile of described changes did not exactly correspond to changes in epileptic afterdischarges supporting the possibility that afterdischarges did not arise from early monosynaptic components of responses. In spite of transient nature of changes they can reflect delayed or more probably modified brain development., J. Tchekalarova, H. Kubová, P. Mareš., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public