Objective: To evaluate the anticonvulsant effect of the essential oil of Myrothamnus moschatus(M. moschatus) in convulsion induced by pentylenetetrazole and picrotoxin in rodent models.Methods: The essential oil of th...Objective: To evaluate the anticonvulsant effect of the essential oil of Myrothamnus moschatus(M. moschatus) in convulsion induced by pentylenetetrazole and picrotoxin in rodent models.Methods: The essential oil of the aerial parts of M. moschatus was extracted by steam distillation. Thereafter, it was injected subcutaneously to rats and mice at escalating doses(0.1–0.8 m L/kg). Ten minutes after drug injection, pentylenetetrazole was injected intraperitoneally to rats and picrotoxin was administered to mice by the same route.Diazepam served as the positive control. Every single animal was placed into transparent cage and observed for convulsive behavior for 30 min by using ordinary security cameras connected to a video recorder. Death occurring for a period of 24 h was also recorded.Results: The essential oil at 0.8 m L/kg completely arrested the pentylenetetrazole-induced convulsion without any sedative effect and delayed its appearance at lower doses, but showed moderate activities on picrotoxin-induced convulsion. For the rats treated with pentylenetetrazole alone, the mortality was 100% within 1 h, but for the rats pre-treated with the essential oil, the mortality was 0%. For the mice treated with picrotoxin, the mortality rate was also 100%, while 20%–100% died in those that had been pre-treated with the oil.Conclusions: The results confirmed at least partly the traditional uses of the smoke of M. moschatus for the management of convulsion, and implied that the essential oil may inhibit the convulsion by GABAergic neuromodulation.展开更多
Stress and emotion are associated with several illnesses from headaches to heart diseases and immune deficiencies to central nervous system. Terminalia arjuna has been referred as traditional Indian medicine for sever...Stress and emotion are associated with several illnesses from headaches to heart diseases and immune deficiencies to central nervous system. Terminalia arjuna has been referred as traditional Indian medicine for several ailments. The present study aimed to elucidate the effect of T. arjuna bark extract(TA) against picrotoxin-induced anxiety. Forty two male Balb/c mice were randomly divided into six experimental groups(n = 7): control, diazepam(1.5 mg·kg^(–1)), picrotoxin(1 mg·kg^(–1)) and three TA treatemt groups(25, 50, and 100 mg/kg). Behavioral paradigms and PCR studies were performed to determine the effect of TA against picrotoxin-induced anxiety. The results showed that TA supplementation increased locomotion towards open arm(EPM) and illuminated area(light-dark box test), and increased rearing frequency(open field test) in a dose dependent manner, compared to picrotoxin(P < 0.05). Furthermore, TA increased number of licks and shocks in Vogel's conflict. PCR studies showed an up-regulation of several genes, such as BDNF, IP_3, D_2L, CREB, GABAA, SOD, GPx, and GR in TA administered groups. In conclusion, alcoholic extract of TA bark showed protective activity against picrotoxin in mice by modulation of genes related to synaptic plasticity, neurotransmitters, and antioxidant enzymes.展开更多
The aversive properties of alcohol can be examined by using ethanol as a conditioning agent in a taste aversion (TA) paradigm. However, there is often variability in how organisms respond to the aversive properties of...The aversive properties of alcohol can be examined by using ethanol as a conditioning agent in a taste aversion (TA) paradigm. However, there is often variability in how organisms respond to the aversive properties of alcohol. Using a selectively bred line of TA-prone (TAP) rats, the present study sought to determine if antagonizing the GABA receptor complex with picrotoxin could block the acquisition of an ethanol-based conditioned aversion to a normally preferred fluid. Fifty TAP rats were randomly divided into 5 groups. In the two experimental groups, rats were pretreated with i.p. injections of low or high doses of the GABA Aantagonist picrotoxin prior to undergoing taste aversion conditioning —wherein consumption of a novel saccharin solution (0.1%) was followed by an i.p. injection of ethanol (1.5 mg/kg). In the primary control group, rats were treated identically, except that isotonic saline was substituted for picrotoxin. In the non-conditioning and pseudo-conditioning control groups, rats did not receive an ethanol-saccharin pairing but did receive a picrotoxin injection. Repeated measures ANOVA revealed that animals in the picrotoxin groups displayed significantly weaker TAs than the primary control group (p 0.05) as measured by post-conditioning, two-bottle saccharin preference scores. Picrotoxin hinders the acquisition of an ethanol-induced TA, thereby supporting the hypothesis that the GABA system plays a central role in ethanol’s motivational effects. Possible mechanisms include 1) picrotoxin attenuates negative effects of ethanol, 2) picrotoxin interferes with the central associative processes that promote TA conditioning or 3) some combination of 1 and 2.展开更多
Objective To examine the effects of urotensin Ⅱ （UⅡ） on the discharges of neurons in CA1 area of hippocampal slices by using extracellular recording technique. Results ①In response to the application of UⅡ （0.3...Objective To examine the effects of urotensin Ⅱ （UⅡ） on the discharges of neurons in CA1 area of hippocampal slices by using extracellular recording technique. Results ①In response to the application of UⅡ （0.3, 3.0, 30.0,300.0 nmol/L, n = 77） into the perfusate for 2 min, the spontaneous discharge rates （SDR） of 63/77 （81.8% ） neurons were significantly decreased in a dose-dependent manner. ②Pretreatment with bicuculline（BIC, 100 μmol/L）, a specific GABAs receptor antagonist, led to a marked increase in the SDR of 6/7 （85.71%） neurons in an epileptiform pattern. The increased discharges were not significantly changed after UⅡ （30.0 nmol/L） was applied into the perfusate for 2 min. ③Pretreatment with picrotoxin （ PIC, 50 μmol/L）, a selective blocker of Cl^- channel, led to an increase in the SDR of all 8/8（ 100% ） neurons. The increased discharges were not influenced by the UⅡ （30.0 nmol/L） applied. ④Application of nitric oxide synthase （NOS） inhibitor N^G nitro-L-arginine methyl ester （L-NAME, 50μmol/L） into the perfusate for 2 min also significantly augmented the SDR of 14/16 （87.5 % ） neurons , then UⅡ （30.0 nmol/L） applied into the perfusate reduced the increased the SDR of all 14/14 （ 100% ） neurons. Conclusion These results suggest that UⅡ may decrease neuronal activity by potentiating GABAA receptor-mediated CI current in hippocampal CA1 neurons, and involved with the mediation of nitric oxide.展开更多
基金Supported by the University Research Fund 2014/2015 of the University of Camerino under the grant number FPI000044
文摘Objective: To evaluate the anticonvulsant effect of the essential oil of Myrothamnus moschatus(M. moschatus) in convulsion induced by pentylenetetrazole and picrotoxin in rodent models.Methods: The essential oil of the aerial parts of M. moschatus was extracted by steam distillation. Thereafter, it was injected subcutaneously to rats and mice at escalating doses(0.1–0.8 m L/kg). Ten minutes after drug injection, pentylenetetrazole was injected intraperitoneally to rats and picrotoxin was administered to mice by the same route.Diazepam served as the positive control. Every single animal was placed into transparent cage and observed for convulsive behavior for 30 min by using ordinary security cameras connected to a video recorder. Death occurring for a period of 24 h was also recorded.Results: The essential oil at 0.8 m L/kg completely arrested the pentylenetetrazole-induced convulsion without any sedative effect and delayed its appearance at lower doses, but showed moderate activities on picrotoxin-induced convulsion. For the rats treated with pentylenetetrazole alone, the mortality was 100% within 1 h, but for the rats pre-treated with the essential oil, the mortality was 0%. For the mice treated with picrotoxin, the mortality rate was also 100%, while 20%–100% died in those that had been pre-treated with the oil.Conclusions: The results confirmed at least partly the traditional uses of the smoke of M. moschatus for the management of convulsion, and implied that the essential oil may inhibit the convulsion by GABAergic neuromodulation.
文摘Stress and emotion are associated with several illnesses from headaches to heart diseases and immune deficiencies to central nervous system. Terminalia arjuna has been referred as traditional Indian medicine for several ailments. The present study aimed to elucidate the effect of T. arjuna bark extract(TA) against picrotoxin-induced anxiety. Forty two male Balb/c mice were randomly divided into six experimental groups(n = 7): control, diazepam(1.5 mg·kg^(–1)), picrotoxin(1 mg·kg^(–1)) and three TA treatemt groups(25, 50, and 100 mg/kg). Behavioral paradigms and PCR studies were performed to determine the effect of TA against picrotoxin-induced anxiety. The results showed that TA supplementation increased locomotion towards open arm(EPM) and illuminated area(light-dark box test), and increased rearing frequency(open field test) in a dose dependent manner, compared to picrotoxin(P < 0.05). Furthermore, TA increased number of licks and shocks in Vogel's conflict. PCR studies showed an up-regulation of several genes, such as BDNF, IP_3, D_2L, CREB, GABAA, SOD, GPx, and GR in TA administered groups. In conclusion, alcoholic extract of TA bark showed protective activity against picrotoxin in mice by modulation of genes related to synaptic plasticity, neurotransmitters, and antioxidant enzymes.
文摘The aversive properties of alcohol can be examined by using ethanol as a conditioning agent in a taste aversion (TA) paradigm. However, there is often variability in how organisms respond to the aversive properties of alcohol. Using a selectively bred line of TA-prone (TAP) rats, the present study sought to determine if antagonizing the GABA receptor complex with picrotoxin could block the acquisition of an ethanol-based conditioned aversion to a normally preferred fluid. Fifty TAP rats were randomly divided into 5 groups. In the two experimental groups, rats were pretreated with i.p. injections of low or high doses of the GABA Aantagonist picrotoxin prior to undergoing taste aversion conditioning —wherein consumption of a novel saccharin solution (0.1%) was followed by an i.p. injection of ethanol (1.5 mg/kg). In the primary control group, rats were treated identically, except that isotonic saline was substituted for picrotoxin. In the non-conditioning and pseudo-conditioning control groups, rats did not receive an ethanol-saccharin pairing but did receive a picrotoxin injection. Repeated measures ANOVA revealed that animals in the picrotoxin groups displayed significantly weaker TAs than the primary control group (p 0.05) as measured by post-conditioning, two-bottle saccharin preference scores. Picrotoxin hinders the acquisition of an ethanol-induced TA, thereby supporting the hypothesis that the GABA system plays a central role in ethanol’s motivational effects. Possible mechanisms include 1) picrotoxin attenuates negative effects of ethanol, 2) picrotoxin interferes with the central associative processes that promote TA conditioning or 3) some combination of 1 and 2.
文摘Objective To examine the effects of urotensin Ⅱ （UⅡ） on the discharges of neurons in CA1 area of hippocampal slices by using extracellular recording technique. Results ①In response to the application of UⅡ （0.3, 3.0, 30.0,300.0 nmol/L, n = 77） into the perfusate for 2 min, the spontaneous discharge rates （SDR） of 63/77 （81.8% ） neurons were significantly decreased in a dose-dependent manner. ②Pretreatment with bicuculline（BIC, 100 μmol/L）, a specific GABAs receptor antagonist, led to a marked increase in the SDR of 6/7 （85.71%） neurons in an epileptiform pattern. The increased discharges were not significantly changed after UⅡ （30.0 nmol/L） was applied into the perfusate for 2 min. ③Pretreatment with picrotoxin （ PIC, 50 μmol/L）, a selective blocker of Cl^- channel, led to an increase in the SDR of all 8/8（ 100% ） neurons. The increased discharges were not influenced by the UⅡ （30.0 nmol/L） applied. ④Application of nitric oxide synthase （NOS） inhibitor N^G nitro-L-arginine methyl ester （L-NAME, 50μmol/L） into the perfusate for 2 min also significantly augmented the SDR of 14/16 （87.5 % ） neurons , then UⅡ （30.0 nmol/L） applied into the perfusate reduced the increased the SDR of all 14/14 （ 100% ） neurons. Conclusion These results suggest that UⅡ may decrease neuronal activity by potentiating GABAA receptor-mediated CI current in hippocampal CA1 neurons, and involved with the mediation of nitric oxide.
