Evaluation of anticonvulsant and antiepileptogenic activity of Euphorbia nivulia in PTZ-induced kindling model of epilepsy in mice.

Epilepsy remains a major chronic neurological disorder with significantly higher refractory seizure rate. Based on the folk medicine literature, we explored the anticonvulsant and antiepileptogenic activity of aqueous ethanolic extracts of Fumaria indica, Euphorbia lactea, Euphorbia helioscopia, Neurada procumbens, and Euphorbia nivulia. The acute anticonvulsant activity of the extracts was determined at different concentrations in different groups of Swiss albino mice. Among all the materials tested, the ethanolic extracts of Euphorbia nivulia (eth-EN) alone was found to exhibit concentration-dependent anticonvulsant effects when evaluated against the acute convulsant dose of Pentylenetetrazole (PTZ, 90mg/kg, s.c.). eth-EN extract at 100mg/kg i.p concentration showed maximum protection against the PTZ induced mortality (P<0.05). eth-EN (100mg/kg) treated animals also showed significant reduction in the progression of epileptogenesis (P<0.05) when tested against the PTZ-induced (50mg/kg s.c.) chemical kindling model of epilepsy. The FT-IR spectra of this extract showed both known and unknown spectral peaks from which the presence of the functional groups; i.e. aromatics, diketones, alkenes, carbonyls, carboxylic acids and amide compounds were confirmed. The unknown peaks strongly suggested the presence of novel compounds that may be responsible for its anticonvulsant and antiepileptogenic activity.

A single dose of cocaine potentiates glutamatergic synaptic transmission onto locus coeruleus neurons.

The brainstem locus coeruleus (LC), the primary norepinephrinergic (NE) nucleus in the brain, has been implicated in the abuse of drugs such as opioids. However, whether and how the LC-NE system is involved in cocaine addiction remains elusive. Here, we demonstrated cocaine-evoked synaptic plasticity of glutamatergic transmission onto LC neurons as one of the earliest traces occurring after a single injection of cocaine. Twenty-four hours after mice were injected intraperitoneally with cocaine, the evoked α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) mediated synaptic transmission onto LC neurons were strongly potentiated without major effect on N-methyl-d-aspartate receptor (NMDAR) mediated synaptic transmission. Compared with saline-pretreated mice, AMPAR-mediated excitatory postsynaptic currents (EPSCs) of cocaine-pretreated mice showed a marked inward rectification, demonstrating the insertion of GluR2-lacking AMPARs to plasma membrane. In addition, the single injection of cocaine did not affect presynaptic glutamate release probability measured by paired pulse ratio. Furthermore, we found that the cocaine-induced potentiation of AMPAR EPSCs could be blocked by prazosin, an inhibitor of α1-adrenoreceptor (AR), indicating that cocaine increases AMPAR transmission via α1-ARs. These results reveal that LC-NE serves as an initial target of drug intake.

Novel green nano composites films fabricated by indigenously synthesized graphene oxide and chitosan.

Graphene oxide (GO) was indigenously synthesized from graphite using standard Hummers method. Chitosan-graphene oxide green composite films were fabricated by mixing aqueous solution of chitosan and GO using dilute acetic acid as a solvent for chitosan. Chitosan of different viscosity and calculated molecular weight was used keeping amount of GO constant in each composite film. The structural properties, thermal stability and mechanical properties of the composite films were investigated using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and tensile test. FTIR studies revealed the successful synthesis of GO from graphite powder and it was confirmed that homogenous blending of chitosan and GO was promising due to oxygenated functional groups on the surface of GO. XRD indicated effective conversion of graphite to GO as its strong peak observed at 11.06° as compared to pristine graphite which appeared at 26°. Moreover, mechanical analysis confirmed the effect of molecular weight on the mechanical properties of chitosan-GO composites showing that higher molecular weight chitosan composite (GOCC-1000) showed best strength (higher than 3GPa) compared to other composite films. Thermal stability of GOCC-1000 was enhanced for which residual content increased up to 56% as compared to the thermal stability of GOCC-200 whose residue was restricted to only 24%. The morphological analysis of the composites sheets by SEM was smooth having dense structure and showed excellent interaction, miscibility, compatibility and dispersion of GO with chitosan. The prepared composite films find their applications as biomaterials in different biomedical fields.