Wyniki wyszukiwania

1

Divergent effects of bicuculline and picrotoxin on ketamine-induced apneustic breathing

100%

Budzinska K.

Journal of Physiology and Pharmacology. Supplement

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2005

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tom 56

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nr 4

39-46

This study tested the potential role of inhibitory neurotransmission in the mechanism of apneustic respiration evoked by ketamine, an NMDA receptors antagonist. In the experiments performed in anesthetized, paralyzed, and ventilated cats, ketamine, in a dose of 0.5 mg/kg, was administered before and after GABAA receptor blockade with picrotoxin or bicuculline; all agents were given intravenously. Ketamine elicited a transient, hourlong apneustic respiration consisting of an increase in inspiratory duration and a decrease in inspiratory neural amplitude. After prior administration of picrotoxin, but not bicuculline, the maximum apneustic-like prolongation of inspiration evoked by ketamine was considerably reduced. The results suggest that the GABA receptor subunits specifically sensitive to picrotoxin play a role in shaping the ketamine-induced apneustic breathing.

2

Hypoglossal and phrenic nerve responses to changes in oxygen tension during picrotoxin-induced seizures in the rat

84%

Budzinska K.

Journal of Physiology and Pharmacology. Supplement

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2004

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tom 55

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nr 3

31-39

The aim of this study was to examine the response of phrenic and hypoglossal motor outputs to hyperoxia and 11% hypoxia during picrotoxin-induced seizures. Adult rats were anesthetized with a mixture of urethane with alpha-chloralose. The animals were bilaterally vagotomized, paralyzed, and artificially ventilated. Picrotoxin was administered intravenously in a cumulative dose until seizures occurred. The response to changes in oxygen tension was studied after the convulsive dose of picrotoxin and compared with the baseline level. The results show that the picrotoxin-induced seizures evoked a complex respiratory response that consisted of an augmentation of phrenic and hypoglossal nerve activities and irregular disturbances in phasic respiratory discharges. The excitation of the hypoglossal activity appeared earlier and showed a more irregular pattern than that of the phrenic activity. Hyperoxia elicited a similar decrease in neural respiratory outputs during the control and seizure conditions, suggesting the unaltered peripheral chemoreceptor mechanism. In the pre-seizure condition, hypoxia caused an initial excitation of the phrenic and hypoglossal outputs followed by some decline of the effect. During seizures, the striking effect of hypoxia was a decrease of the respiratory rate. A biphasic response to hypoxia was maintained in the hypoglossal activity due to stimulation of the hypoglossal amplitude. In contrast, in the phrenic activity the excitatory phase of hypoxia was absent and depression ensued. The mechanism underlying the facilitation of hypoxic respiratory depression during seizures is discussed.

3

Short-term depression of inspiratory activity following tonic vagal stimulation

84%

Budzinska K., Ilasz R.

Journal of Physiology and Pharmacology. Supplement

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2006

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tom 57

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nr 4

55-61

This study tested the role of inhibitory neurotransmission in the glutaminergic control of short-term depression (STD) of the inspiratory activity initiated by sustained stimulation of the vagus nerve in anesthetized and vagotomized cats. STD, calculated from the integrated phrenic nerve signal, lasted longer when glutaminergic neurotransmission was inhibited by ketamine, a NMDA receptor antagonist. Application of picrotoxin, a GABAA receptor antagonist, reversed the effect of ketamine and shortened the STD duration below that present in the control condition. The results showed that alternation of the neural excitability by antagonists of excitatory and inhibitory neurotransmission modulates the STD of inspiratory activity, evoked by vagal stimulation. The STD depends on the state of neural excitability and is easier accomplished when the excitability is on the high side.

4

Influence of several convulsants on the protective activity of a non-competitive AMPA-kainate antagonist, LY 300164, and lamotrigine against maximal electroshock in mice

84%

Borowicz K. K., Swiader M., Zgrajka W., Sawulski C., Turski W. A., Czuczwar S. J.

Journal of Physiology and Pharmacology

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2002

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tom 53

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nr 4,2

Aminophylline (50-100 mg/kg) and strychnine (0.125-0.5 mg/kg) significantly raised the ED50 values of LY 300164 against maximal electroshock in mice, from 4 to 8 mg/kg (aminophylline 100 mg/kg) and from 3.6 to 11.5 mg/kg (strychnine 0.5 mg/kg). Also, aminophylline (25-50 mg/kg) and strychnine (0.125-0.25 mg/kg) increased the ED50 value of lamotrigine in this test, for instance from 5.5 to 8.0 mg/kg (aminophylline 50 mg/kg) and from 5.2 to 8.9 mg/kg (strychnine 0.25 mg/kg). Moreover, the ED50s values of aminophylline and strychnine for the reduction of the anticonvulsant effect of LY 300164 (7 mg/kg, the dose equal to its ED97 value against maximal electroshock) were 79.9 and 0.2 mg/kg, respectively. The respective ED50 values for the inhibition of the antiseizure action of lamotrigine were 40.9 and 0.2 mg/kg. Neither bicuculline nor picrotoxin affected the protective action of LY 300164 or lamotrigine. Strychnine significantly lowered the plasma concentrations of LY 300164 and this my point to a pharmacokinetic mechanism of the observed interaction. Aminophylline did not affect the plasma concentrations of the studied anticonvulsant drugs and strychnine - that of lamotrigine, so a pharmacokinetic interaction does not seem probable. The present results indicate that the potential of aminophylline and strychnine to attenuate the anticonvulsant activity of conventional antiepileptics is extended to LY 300164 and lamotrigine.

5

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Evaluation of antiepileptic activity of methanolic leaves extract of Tragia involucrata Linn. in mice

67%

Varma G. G., Mathai B. K., Das K., Gowda G., Rammohan S., Einstein J. W.

International Letters of Natural Sciences

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2014

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tom 12

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nr 2

The present investigation was aimed to study an antiepileptic activity of methanolic extract of Tragia involucrata Linn in mice. In vivo screening models like maximal electroshock-induced convulsion (MES), pentylenetetrazole (PTZ) and picrotoxin (PTX) induced models are used to evaluate the antiepileptic effects of the extracts. The biochemical estimation was done by measuring the lipid peroxidation and reduced glutathione (GSH). In the MES induced convulsion, methanolic extract of Tragia involucrata (METI) at high dose (800 mg/kg body weight), showed high significant inhibition on tonic hind limb extension (THLE, 6.83 ±0.30***) and decrease in duration of stupor period (108.7 ±6.53***). In PTZ and PTX induced model METI (400 mg/kg and 800 mg/kg) showed significant delay on the onset of convulsions, decreased duration of convulsion and reduced mortality significantly. It also showed significant decrease in brain MDA level in lipid peroxidation profile, and increase in the brain glutathione levels in mice against PTZ induced convulsion. The results confirmed that Tragia involucrata Linn possesses dose dependent antiepileptic activity.

6

Exogenous melatonin abolishes mechanical allodynia but not thermal hyperalgesia in neuropathic pain. The role of the opioid system and benzodiazepine-GABAergic mechanism

67%

Zurowski D., Nowak L., Machowska A., Wordliczek J., Thor P. J.

Journal of Physiology and Pharmacology

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2012

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tom 63

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nr 6

7

Strychnine antagonizes GABA-evoked 36 CI- uptake in membrane vesicles from rat and rabbit cerebral cortex

59%

Puka M., Lazarewicz J. W.

Acta Neurobiologiae Experimentalis

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1993

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tom 53

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nr 4

Ograniczanie wyników

Divergent effects of bicuculline and picrotoxin on ketamine-induced apneustic breathing

Hypoglossal and phrenic nerve responses to changes in oxygen tension during picrotoxin-induced seizures in the rat

Short-term depression of inspiratory activity following tonic vagal stimulation

Influence of several convulsants on the protective activity of a non-competitive AMPA-kainate antagonist, LY 300164, and lamotrigine against maximal electroshock in mice

Evaluation of antiepileptic activity of methanolic leaves extract of Tragia involucrata Linn. in mice

Exogenous melatonin abolishes mechanical allodynia but not thermal hyperalgesia in neuropathic pain. The role of the opioid system and benzodiazepine-GABAergic mechanism

Strychnine antagonizes GABA-evoked 36 CI- uptake in membrane vesicles from rat and rabbit cerebral cortex