Aim To investigate the synergistic effect of the combination of pinellia total alkaloid （PTA） and uncaria total alkaloid （UTA）, and explore the mechanism of anticonvulsant action. Methods Anticonvulsant and toxic ...Aim To investigate the synergistic effect of the combination of pinellia total alkaloid （PTA） and uncaria total alkaloid （UTA）, and explore the mechanism of anticonvulsant action. Methods Anticonvulsant and toxic effect profiles of combinations of PTA with UTA, alone and at three fixed ratios of 1：4, 1 ：1, 4：1, were evaluated in maximal electroshock （MES）-induced seizures and acute toxicity test in mice. Respective ED50 and LD50 were calculated with Bliss＇s method. Their synergistic effect were evaluated by isobolographic analysis and allowed the determination of benefit indices （BI） for respective combinations. The model of convulsive rats kindled by penicillin topically injected into cortex was used to investigated the content of Glu, Asp, Gly and GABA in hippocampus using high performance liquid chromatography （HPLC）. Results Combinations of PTA and UTA at the ratio of 4：1 were synergistic in MES test and antagonistic in acute toxicity test, showing the best profile for combinations of PTA with UTA. In contrast, the ratios of 1 ：4 and 1 ： 1, despite synergistic in MES test, were additive in acute toxicity test. The 4：1 combination and two drugs alone significantly decreased Glu level and increased GABA level in the hippocampus, but the GABA level in the 4：1 combination group was higher than that in the two drugs alone groups. They did not have significant influence on the levels of ASp and Gly. Conclusion Combinations of PTA and UTA at 4：1 ratio demonstrated synergistic effect in anticonvulsant action and antagonistic effect in toxicity. The anticonvulsant mechanism might be related to decreasing the excitability of Glutamatergic neurons and increasing the inhibition of GABAergic neurons.展开更多
The antiepileptic effect of 4-amino-2-methyl-cantharidinimide（AMC） was reported,but its mechanism remains unknown.In this study,we investigated the effects of AMC on a rat model of penicillin-induced epilepsy.The do...The antiepileptic effect of 4-amino-2-methyl-cantharidinimide（AMC） was reported,but its mechanism remains unknown.In this study,we investigated the effects of AMC on a rat model of penicillin-induced epilepsy.The doses of 88 and 22 mg/kg AMC and the dose of 154 mg/kg sodium valproate（VPA） were administered intragastrically（i.g.） 30 min before penicillin injection,respectively.The epileptiform activity was verified by electrocorticographic（ECoG） recordings.The levels of GABA and GABAC receptors in hippocampus were determined by immunohistochemistry,and real-time polymerase chain reaction（RT-PCR） technique was used to detect the mRNA expression of GABAC receptor ρ2.The mean frequency and amplification of spike epileptiform activity were significantly decreased in AMC and VPA-pretreated rats compared with those of non-pretreated penicillin-induced epilepsy（PIE） group.The levels of GABA,GABAC receptors and the mRNA expression of GABAC receptors ρ2 in AMC and VPA-pretreated rats were significantly increased as compared with PIE group.These findings indicate that AMC and VPA have an antiepileptic effect on PIE in rats,and the antiepileptic effect of AMC may be mediated by the GABAC receptors and GABA.展开更多
基金Natural Science Foundation of Shanxi Province(No 20041109).
文摘Aim To investigate the synergistic effect of the combination of pinellia total alkaloid （PTA） and uncaria total alkaloid （UTA）, and explore the mechanism of anticonvulsant action. Methods Anticonvulsant and toxic effect profiles of combinations of PTA with UTA, alone and at three fixed ratios of 1：4, 1 ：1, 4：1, were evaluated in maximal electroshock （MES）-induced seizures and acute toxicity test in mice. Respective ED50 and LD50 were calculated with Bliss＇s method. Their synergistic effect were evaluated by isobolographic analysis and allowed the determination of benefit indices （BI） for respective combinations. The model of convulsive rats kindled by penicillin topically injected into cortex was used to investigated the content of Glu, Asp, Gly and GABA in hippocampus using high performance liquid chromatography （HPLC）. Results Combinations of PTA and UTA at the ratio of 4：1 were synergistic in MES test and antagonistic in acute toxicity test, showing the best profile for combinations of PTA with UTA. In contrast, the ratios of 1 ：4 and 1 ： 1, despite synergistic in MES test, were additive in acute toxicity test. The 4：1 combination and two drugs alone significantly decreased Glu level and increased GABA level in the hippocampus, but the GABA level in the 4：1 combination group was higher than that in the two drugs alone groups. They did not have significant influence on the levels of ASp and Gly. Conclusion Combinations of PTA and UTA at 4：1 ratio demonstrated synergistic effect in anticonvulsant action and antagonistic effect in toxicity. The anticonvulsant mechanism might be related to decreasing the excitability of Glutamatergic neurons and increasing the inhibition of GABAergic neurons.
基金Scientific and Technological Innovation Foundation of Shanxi Medical University (Grant No. 01200804)
文摘The antiepileptic effect of 4-amino-2-methyl-cantharidinimide（AMC） was reported,but its mechanism remains unknown.In this study,we investigated the effects of AMC on a rat model of penicillin-induced epilepsy.The doses of 88 and 22 mg/kg AMC and the dose of 154 mg/kg sodium valproate（VPA） were administered intragastrically（i.g.） 30 min before penicillin injection,respectively.The epileptiform activity was verified by electrocorticographic（ECoG） recordings.The levels of GABA and GABAC receptors in hippocampus were determined by immunohistochemistry,and real-time polymerase chain reaction（RT-PCR） technique was used to detect the mRNA expression of GABAC receptor ρ2.The mean frequency and amplification of spike epileptiform activity were significantly decreased in AMC and VPA-pretreated rats compared with those of non-pretreated penicillin-induced epilepsy（PIE） group.The levels of GABA,GABAC receptors and the mRNA expression of GABAC receptors ρ2 in AMC and VPA-pretreated rats were significantly increased as compared with PIE group.These findings indicate that AMC and VPA have an antiepileptic effect on PIE in rats,and the antiepileptic effect of AMC may be mediated by the GABAC receptors and GABA.
