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Walter G. Besio - One of the best experts on this subject based on the ideXlab platform.

  • Sensor integration of multiple tripolar concentric ring electrodes improves Pentylenetetrazole-Induced Seizure onset detection in rats
    2012 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2012
    Co-Authors: Oleksandr Makeyev, Quan Ding, Walter G. Besio
    Abstract:

    As epilepsy affects approximately one percent of the world population, electrical stimulation of the brain has recently shown potential for additive Seizure control therapy. Previously, we applied noninvasive transcranial focal stimulation via tripolar concentric ring electrodes on the scalp of rats after inducing Seizures with pentylenetetrazole. We developed a system to detect Seizures and automatically trigger the stimulation and evaluated the system on the electrographic activity from rats. In this preliminary study we propose and validate a novel Seizure onset detection algorithm based on exponentially embedded family. Unlike the previously proposed approach it integrates the data from multiple electrodes allowing an improvement of the detector performance.

  • transcranial focal stimulation via concentric ring electrodes reduced power of pentylenetetrazole induced Seizure activity in rat electroencephalogram
    International Conference of the IEEE Engineering in Medicine and Biology Society, 2011
    Co-Authors: Oleksandr Makeyev, Kanthaiah Koka, Walter G. Besio
    Abstract:

    As epilepsy affects approximately one percent of the world population, electrical stimulation of the brain has recently shown potential for additive Seizure control therapy. In this study we applied noninvasive transcranial focal stimulation (TFS) via concentric ring electrodes on the scalp of rats after inducing Seizures with pentylenetetrazole (PTZ) to assess the effect of TFS on the electrographic activity. Grand average power spectral densities were calculated to compare different stages of Seizure development. They showed a significant difference between the TFS treated group and the control group. In case of the TFS treated group, after TFS, the power spectral density was reduced further towards a pre-Seizure “baseline” than it was for the control group. The difference is the most drastic in delta, theta and alpha frequency bands. Application of general likelihood ratio test showed that TFS significantly (p<0.001) reduced the power of electrographic Seizure activity in the TFS treated group compared to controls in more than 86% of the cases. These results suggest that TFS may have an anticonvulsant effect.

  • Transcranial focal stimulation via concentric ring electrodes reduced power of Pentylenetetrazole-Induced Seizure activity in rat electroencephalogram
    2011 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2011
    Co-Authors: Oleksandr Makeyev, Kanthaiah Koka, Walter G. Besio
    Abstract:

    As epilepsy affects approximately one percent of the world population, electrical stimulation of the brain has recently shown potential for additive Seizure control therapy. In this study we applied noninvasive transcranial focal stimulation (TFS) via concentric ring electrodes on the scalp of rats after inducing Seizures with pentylenetetrazole (PTZ) to assess the effect of TFS on the electrographic activity. Grand average power spectral densities were calculated to compare different stages of Seizure development. They showed a significant difference between the TFS treated group and the control group. In case of the TFS treated group, after TFS, the power spectral density was reduced further towards a pre-Seizure “baseline” than it was for the control group. The difference is the most drastic in delta, theta and alpha frequency bands. Application of general likelihood ratio test showed that TFS significantly (p

Oleksandr Makeyev - One of the best experts on this subject based on the ideXlab platform.

  • Sensor integration of multiple tripolar concentric ring electrodes improves Pentylenetetrazole-Induced Seizure onset detection in rats
    2012 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2012
    Co-Authors: Oleksandr Makeyev, Quan Ding, Walter G. Besio
    Abstract:

    As epilepsy affects approximately one percent of the world population, electrical stimulation of the brain has recently shown potential for additive Seizure control therapy. Previously, we applied noninvasive transcranial focal stimulation via tripolar concentric ring electrodes on the scalp of rats after inducing Seizures with pentylenetetrazole. We developed a system to detect Seizures and automatically trigger the stimulation and evaluated the system on the electrographic activity from rats. In this preliminary study we propose and validate a novel Seizure onset detection algorithm based on exponentially embedded family. Unlike the previously proposed approach it integrates the data from multiple electrodes allowing an improvement of the detector performance.

  • transcranial focal stimulation via concentric ring electrodes reduced power of pentylenetetrazole induced Seizure activity in rat electroencephalogram
    International Conference of the IEEE Engineering in Medicine and Biology Society, 2011
    Co-Authors: Oleksandr Makeyev, Kanthaiah Koka, Walter G. Besio
    Abstract:

    As epilepsy affects approximately one percent of the world population, electrical stimulation of the brain has recently shown potential for additive Seizure control therapy. In this study we applied noninvasive transcranial focal stimulation (TFS) via concentric ring electrodes on the scalp of rats after inducing Seizures with pentylenetetrazole (PTZ) to assess the effect of TFS on the electrographic activity. Grand average power spectral densities were calculated to compare different stages of Seizure development. They showed a significant difference between the TFS treated group and the control group. In case of the TFS treated group, after TFS, the power spectral density was reduced further towards a pre-Seizure “baseline” than it was for the control group. The difference is the most drastic in delta, theta and alpha frequency bands. Application of general likelihood ratio test showed that TFS significantly (p<0.001) reduced the power of electrographic Seizure activity in the TFS treated group compared to controls in more than 86% of the cases. These results suggest that TFS may have an anticonvulsant effect.

  • Transcranial focal stimulation via concentric ring electrodes reduced power of Pentylenetetrazole-Induced Seizure activity in rat electroencephalogram
    2011 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2011
    Co-Authors: Oleksandr Makeyev, Kanthaiah Koka, Walter G. Besio
    Abstract:

    As epilepsy affects approximately one percent of the world population, electrical stimulation of the brain has recently shown potential for additive Seizure control therapy. In this study we applied noninvasive transcranial focal stimulation (TFS) via concentric ring electrodes on the scalp of rats after inducing Seizures with pentylenetetrazole (PTZ) to assess the effect of TFS on the electrographic activity. Grand average power spectral densities were calculated to compare different stages of Seizure development. They showed a significant difference between the TFS treated group and the control group. In case of the TFS treated group, after TFS, the power spectral density was reduced further towards a pre-Seizure “baseline” than it was for the control group. The difference is the most drastic in delta, theta and alpha frequency bands. Application of general likelihood ratio test showed that TFS significantly (p

Jarogniew J. Luszczki - One of the best experts on this subject based on the ideXlab platform.

  • Pharmacodynamic and pharmacokinetic interaction profiles of levetiracetam in combination with gabapentin, tiagabine and vigabatrin in the mouse Pentylenetetrazole-Induced Seizure model: an isobolographic analysis.
    European Journal of Pharmacology, 2009
    Co-Authors: Monika Dudra-jastrzębska, Marta Andres-mach, Marcin Sielski, Neville Ratnaraj, Philip N. Patsalos, Stanisław J. Czuczwar, Jarogniew J. Luszczki
    Abstract:

    Abstract To characterize the interactions between levetiracetam and the antiepileptic drugs gabapentin, tiagabine, and vigabatrin in suppressing Pentylenetetrazole-Induced clonic Seizures in mice, type II isobolographic analysis was used. Clonic Seizures were evoked in Albino Swiss mice by subcutaneous injection of pentylenetetrazole at its CD97(98 mg/kg). Adverse-effect profiles with respect to motor performance, long-term memory and skeletal muscular strength were measured along with total brain antiepileptic drug concentrations. The combination of gabapentin with levetiracetam at the fixed-ratios of 2:1, 1:1, 1:2, and 1:4 were supra-additive (synergistic) in terms of Seizure suppression whilst the combination at the fixed-ratio of 4:1 was additive. Tiagabine with levetiracetam and vigabatrin with levetiracetam at the fixed-ratios of 1:25, 1:50, 1:100, 1:200, and 1:400 and at 2:1, 3:1, 4:1, 6:1, 8:1, and 16:1 were additive, respectively. No acute adverse effects were observed. Measurement of total brain antiepileptic drug concentrations revealed that levetiracetam in combination with gabapentin at the fixed-ratio of 1:4 significantly elevated (21%) total brain gabapentin concentrations. In contrast, levetiracetam was without affect on tiagabine or vigabatrin concentrations and co-administration with gabapentin, tiagabine or vigabatrin had no effect on levetiracetam brain concentrations, indicating the pharmacodynamic nature of interaction between these antiepileptic drugs in the mouse pentylenetetrazole model. The combination of gabapentin with levetiracetam at the fixed-ratios of 2:1, 1:1, 1:2, and 1:4 appears to be particularly favorable combination exerting supra-additive interaction in suppressing Pentylenetetrazole-Induced Seizures, although there is a pharmacokinetic contribution to the interaction between levetiracetam and gabapentin at the fixed-ratio of 1:4. Levetiracetam in combination with tiagabine and vigabatrin appear to be neutral combinations producing only additivity in the mouse pentylenetetrazole model.

  • Interactions of tiagabine with ethosuximide in the mouse Pentylenetetrazole-Induced Seizure model: an isobolographic analysis for non-parallel dose-response relationship curves
    Naunyn-Schmiedeberg's Archives of Pharmacology, 2008
    Co-Authors: Jarogniew J. Luszczki
    Abstract:

    The aim of this study was to characterize the interaction between tiagabine (TGB) and ethosuximide (ETS), two antiepileptic drugs, in pentylenetetrazole (PTZ)-induced clonic Seizures in mice using isobolographic analysis. The nature of the interaction between the drugs administered in combination was ascertained by estimating plasma and brain concentrations of ETS and TGB using fluorescence polarization immunoassay (FPIA) and high-performance liquid chromatography (HPLC). The results indicated that both drugs produced clear anticonvulsant effects against PTZ-induced clonic Seizures in mice, but that their dose-response relationship curves (DRRCs) were not parallel, consequently necessitating the isobolographic analysis for non-parallel DRRCs. The isobolographic analysis revealed that the combination of TGB with ETS at the fixed-ratio of 1:1 exerted an additive interaction against PTZ-induced clonic Seizures in mice. FPIA documented that TGB significantly elevated brain ETS concentrations (by 64%), while having no effect on plasma ETS concentrations in experimental animals. In contrast, ETS had no significant impact on plasma and brain concentrations of TGB in mice, as measured by HPLC. It can be concluded that the additive interaction between TGB and ETS at the fixed-ratio of 1:1 in the PTZ test was complicated by a significant pharmacokinetic increase in total brain ETS concentrations. At present, there are no recommendations to use this drug combination in epileptic patients.

Ahmad Reza Dehpour - One of the best experts on this subject based on the ideXlab platform.

  • The additive effect of opioids and nitric oxide in increasing Pentylenetetrazole-Induced Seizure threshold in cholestatic mice
    Journal of Gastroenterology and Hepatology, 2020
    Co-Authors: Houman Homayoun, Mohammad Sayyah, Ahmad Reza Dehpour
    Abstract:

    BACKGROUND: Accumulation of endogenous opioids and overproduction of nitric oxide has been reported in cholestatic mice. It is well known that endogenous opioids and nitric oxide alter the susceptibility of experimental animals to different models of Seizure. METHODS: The alterations in clonic Seizure thresholds, induced by pentylenetetrazole from 1 to 6 days after bile duct ligation, were evaluated in mice. Whether the pretreatment of cholestatic mice with different doses of opioid receptor antagonist naltrexone, or nitric oxide inhibitor N(omega)-nitro-L-arginine methyl ester would have changed the clonic Seizure threshold was also examined. RESULTS: While in sham-operated mice the clonic Seizure threshold was similar to that of the thresholds in unoperated controls, a time-dependent increase in the threshold was observed in cholestatic mice, reaching a peak on day 3 after bile duct ligation and declining partially after the 4th day. Chronic pretreatment with naltrexone (2, 5 and 10 mg/kg, i.p.) reversed the increased threshold in cholestatic mice on day 3 after operation in a dose-dependent manner with the highest doses used restoring the threshold to that of the control animals. A similar reversal of the increased threshold was observed after acute (1, 3 and 10 mg/kg, i.p.) or chronic (10 mg/kg, i.p. for 4 days) pretreatment with N(omega)-nitro-L-arginine methyl ester. Moreover, concurrent administration of doses of N(omega)-nitro-L-arginine methyl ester and naltrexone that each separately induced a partial reversal of increased Seizure threshold in cholestasis caused a complete restoring of the threshold to the control level. CONCLUSIONS: Based on these findings, both opioid receptors and nitric oxide may be involved in the dramatic increase in Pentylenetetrazole-Induced Seizure threshold in cholestasis.

  • The interaction of melatonin and agmatine on Pentylenetetrazole-Induced Seizure threshold in mice.
    Epilepsy & Behavior, 2011
    Co-Authors: Leila Moezi, Hamed Shafaroodi, Abolfazl Hojati, Ahmad Reza Dehpour
    Abstract:

    article i nfo Melatonin, the major hormone produced by the pineal gland, has a number of functions in mammals, for example, its function as an anticonvulsant. Agmatine, a biogenic amine formed by decarboxylation of L- arginine by arginine decarboxylase, also has anticonvulsant effects. This study investigated the effect of the interaction of melatonin and agmatine on Seizure susceptibility in the mouse model of pentylenetetrazole (PTZ)-induced clonic Seizures. Further, the researchers investigated the involvement of melatonin receptors in this interaction using luzindole, a ML1/2 receptor antagonist and prazosin, a ML3 receptor antagonist. Melatonin, at 40 and 80 mg/kg, and agmatine, at 10 and 20 mg/kg, exerted anticonvulsant effects. Luzindole, at 1.25 and 2.5 mg/kg, or prazosin, at 0.5 mg/kg, did not change the Seizure threshold as compared with that of vehicle-treated mice. The anticonvulsant effect of melatonin (40 and 80 mg/kg) was prevented by luzindole (2.5 mg/kg) (Pb0.001) but not prazosin (0.5 mg/kg), indicating the possible involvement of ML1/2 receptors in the anticonvulsant effect of melatonin. Agmatine (5 mg/kg) significantly increased the anticonvulsant effect of both the noneffective dose (20 mg/kg) (Pb0.05) and the effective dose (80 mg/kg) (Pb0.001) of melatonin. Luzindole (2.5 mg/kg), but not prazosin (0.5 mg/kg), decreased the anticonvulsant effect of agmatine (20 mg/kg) (Pb0.05). Luzindole (2.5 mg/kg), but not prazosin (0.5 mg/kg), also decreased the Seizure threshold when agmatine (5 mg/kg) was administered before melatonin (20 mg/kg); the decrease was significant compared with that of the group that received only agmatine and melatonin (Pb0.001). In conclusion, melatonin and agmatine exhibit an additive effect in decreasing Pentylenetetrazole-Induced Seizure threshold in mice, probably through ML1/2 receptors.

  • ATP-sensitive potassium channels contribute to the time-dependent alteration in the Pentylenetetrazole-Induced Seizure threshold in diabetic mice.
    Seizure-european Journal of Epilepsy, 2009
    Co-Authors: Mehdi Ghasemi, Hamed Shafaroodi, Ali Reza Karimollah, Taha Gholipour, Behtash Ghazi Nezami, Farzad Ebrahimi, Ahmad Reza Dehpour
    Abstract:

    Abstract Although there is evidence that diabetes affects Seizure susceptibility, the underlying mechanism has not been completely understood. Several studies also suggest a pivotal role for K ATP channels in the Seizure modulation. The aim of the present study was to evaluate the Seizure threshold induced by pentylenetetrazole in diabetic mice at different times (3 days, 1–8 weeks) after induction of diabetes with streptozocin and to examine the possible role of ATP-sensitive potassium (K ATP ) channels in this manner. Our data showed a time-dependent alteration in the threshold in diabetic mice, reaching a peak on week 2 after streptozocin injection and declining significantly afterwards. The Seizure threshold in 8-week diabetic mice was even lower than control levels, though the difference was not significant. The K ATP channel opener cromakalim (0.1–30μg/kg, i.p.) significantly increased the Seizure threshold in control mice. Although the K ATP channel blocker glibenclamide (0.5, 1mg/kg) had no effect, it prevented the effects of the potent dose of cromakalim (30μg/kg) on Seizure threshold in control mice. Glibenclamide (1mg/kg, i.p.) also decreased the Seizure threshold in 2-week diabetic mice to the control levels which was blocked by pre-treatment with cromakalim (10μg/kg, i.p.). Cromakalim (10μg/kg, i.p.) significantly increased the Seizure threshold in 8-week diabetic mice which was inhibited by pre-treatment with glibenclamide (1mg/kg, i.p.). We demonstrated a time-dependent alteration in the Pentylenetetrazole-Induced Seizure threshold in diabetic mice. This phenomenon might be due to the probable alteration in the K ATP channel functioning during the diabetic condition.

  • Elevation of Pentylenetetrazole-Induced Seizure threshold in cholestatic mice: interaction between opioid and cannabinoid systems.
    Journal of Gastroenterology and Hepatology, 2007
    Co-Authors: Hamed Shafaroodi, Mehdi Ghasemi, Ahmad Reza Dehpour
    Abstract:

    Background and Aim:  Several studies have reported that endogenous opioid and cannabinoid systems may be involved in some pathophysiological changes occurring in cholestatic liver disease. It is well known that endogenous opioids and cannabinoids alter the susceptibility of experimental animals to different models of Seizure. Methods:  The alterations in Pentylenetetrazole-Induced clonic Seizure thresholds were evaluated from 1 to 6 days after bile duct ligation in mice. Whether the pretreatment of cholestatic mice with different doses of opioid receptor antagonist naltrexone or cannabinoid CB1 receptor antagonist AM251 (AM251) would have changed the clonic Seizure threshold was also examined. Results:  Although the clonic Seizure threshold was similar between sham-operated and unoperated mice, there was a time-dependent increase in the threshold in cholestatic mice, reaching a peak on day 3 after bile duct ligation and declining partially after day 4. Chronic pretreatment with naltrexone (2, 5, and 10 mg/kg) reversed the increased threshold in cholestatic mice on day 3 after operation in a dose-dependent manner with the highest doses used restoring the threshold to that of the control animals. A similar reversal of the increased threshold was observed after acute (0.5, 0.75, and 1 mg/kg) or chronic (0.5 mg/kg for 4 days) pretreatment with AM251. Moreover, concurrent administration of doses of AM251 and naltrexone that each separately induced a partial reversal of increased Seizure threshold in cholestasis caused a complete restoring of the threshold to the control level. Conclusions:  Both opioid and cannabinoid CB1 receptors may be involved in the dramatic increase in Pentylenetetrazole-Induced Seizure threshold in cholestasis.

  • The interaction of cannabinoids and opioids on Pentylenetetrazole-Induced Seizure threshold in mice.
    Neuropharmacology, 2004
    Co-Authors: Hamed Shafaroodi, Leila Moezi, Houman Homayoun, Morteza Samini, Hamed Sadeghipour, Sina Tavakoli, Amir Reza Hajrasouliha, Ahmad Reza Dehpour
    Abstract:

    Abstract Cannabinoid and opioid receptor agonists show functional interactions in a number of their physiological effects. Regarding the Seizure-modulating properties of both classes of receptors, the present study examined the possibility of a functional interaction between these receptors. We used acute systemic administration of cannabinoid selective CB1 receptor agonist (ACPA) and antagonist (AM251) and opioid receptor agonist (morphine) and antagonists (naltrexone and norbinaltorphimine) in a model of clonic Seizure induced by pentylenetetrazole (PTZ). Acute administration of ACPA (1.5–2 mg/kg) increased the PTZ-induced Seizure threshold. In contrast, AM251 (0.5–2 mg/kg) dose-dependently decreased the Seizure threshold. Low dose of AM251 (0.5 mg/kg), which did not alter Seizure threshold by itself, reversed the anticonvulsant effect of ACPA (2 mg/kg), showing a CB1 receptor-mediated mechanism. Naltrexone (1 or 10 mg/kg) but not specific κ-opioid receptor antagonist norbinaltorphimine (5 mg/kg) completely reversed the anticonvulsant effect of ACPA (2 mg/kg). Moreover, the combination of the lower doses of AM251 (0.5 mg/kg) and naltrexone (0.3 mg/kg) had an additive effect in blocking the anticonvulsant effect of ACPA. In accordance with previous reports, morphine exerted biphasic effects on clonic Seizure threshold with anticonvulsant effect at lower (0.5–1 mg/kg) and proconvulsant effect at a higher (30 mg/kg) doses. The pretreatment with AM251 blocked the anticonvulsant effect of morphine at 1 mg/kg, while pretreatment with ACPA (1 mg/kg) potentiated the anticonvulsant effect of morphine at 0.5 mg/kg. The proconvulsant effect of morphine at 30 mg/kg was also inhibited by AM251 (2 mg/kg). A similar interaction between cannabinoids and opioids was also detected on their anticonvulsant effects against the generalized tonic–clonic model of Seizure. In conclusion, cannabinoids and opioids show functional interactions on modulation of Seizure susceptibility.

Kanthaiah Koka - One of the best experts on this subject based on the ideXlab platform.

  • transcranial focal stimulation via concentric ring electrodes reduced power of pentylenetetrazole induced Seizure activity in rat electroencephalogram
    International Conference of the IEEE Engineering in Medicine and Biology Society, 2011
    Co-Authors: Oleksandr Makeyev, Kanthaiah Koka, Walter G. Besio
    Abstract:

    As epilepsy affects approximately one percent of the world population, electrical stimulation of the brain has recently shown potential for additive Seizure control therapy. In this study we applied noninvasive transcranial focal stimulation (TFS) via concentric ring electrodes on the scalp of rats after inducing Seizures with pentylenetetrazole (PTZ) to assess the effect of TFS on the electrographic activity. Grand average power spectral densities were calculated to compare different stages of Seizure development. They showed a significant difference between the TFS treated group and the control group. In case of the TFS treated group, after TFS, the power spectral density was reduced further towards a pre-Seizure “baseline” than it was for the control group. The difference is the most drastic in delta, theta and alpha frequency bands. Application of general likelihood ratio test showed that TFS significantly (p<0.001) reduced the power of electrographic Seizure activity in the TFS treated group compared to controls in more than 86% of the cases. These results suggest that TFS may have an anticonvulsant effect.

  • Transcranial focal stimulation via concentric ring electrodes reduced power of Pentylenetetrazole-Induced Seizure activity in rat electroencephalogram
    2011 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2011
    Co-Authors: Oleksandr Makeyev, Kanthaiah Koka, Walter G. Besio
    Abstract:

    As epilepsy affects approximately one percent of the world population, electrical stimulation of the brain has recently shown potential for additive Seizure control therapy. In this study we applied noninvasive transcranial focal stimulation (TFS) via concentric ring electrodes on the scalp of rats after inducing Seizures with pentylenetetrazole (PTZ) to assess the effect of TFS on the electrographic activity. Grand average power spectral densities were calculated to compare different stages of Seizure development. They showed a significant difference between the TFS treated group and the control group. In case of the TFS treated group, after TFS, the power spectral density was reduced further towards a pre-Seizure “baseline” than it was for the control group. The difference is the most drastic in delta, theta and alpha frequency bands. Application of general likelihood ratio test showed that TFS significantly (p