Anti-epileptic effect of morin against experimental pentylenetetrazol-induced seizures via modulating brain monoamines and oxidative stress

Objective: To evaluate the protective effect of morin against pentylenetetrazol (PTZ)-induced tonic-clonic convulsions in mice. Methods: Swiss albino mice (18-22 g) was used to induce convulsions by intraperitoneal (i.p.) administration of PTZ (90 mg/kg). Mice were either pretreated with morin (10, 20 and 40 mg/kg) or vehicle (distilled water, 10 mg/kg) 45 min before PTZ administration. Various behavioral and biochemical parameters were assessed. Results: PTZ administration resulted in significant production (P<0.001) of tonic-clonic conclusion and mortality in mice. PTZ-induced increase in the duration of convulsion, onset of convulsion and mortality was inhibited significantly by morin (20 and 40 mg/kg) administration. The PTZ-induced decrease in brain GABA, dopamine and Na

Anti-epileptic effect of morin against experimental pentylenetetrazol-inducedseizures via modulating brain monoamines and oxidative stress

Objective: To evaluate the protective effect of morin against pentylenetetrazol (PTZ)-induced tonic-clonic convulsions in mice. Methods: Swiss albino mice (18-22 g) was used to induce convulsions by intraperitoneal (i.p.) administration of PTZ (90 mg/kg). Mice were either pretreated with morin (10, 20 and 40 mg/kg) or vehicle (distilled water, 10 mg/kg) 45 min before PTZ administration. Various behavioral and biochemical parameters were assessed. Results: PTZ administration resulted in significant production (P<0.001) of tonic-clonic conclusion and mortality in mice. PTZ-induced increase in the duration of convulsion, onset of convulsion and mortality was inhibited significantly by morin (20 and 40 mg/kg) administration. The PTZ-induced decrease in brain GABA, dopamine and Na+K+ATPase levels and increase in xanthine oxidase activity were inhibited significantly by morin (20 and 40 mg/kg) treatment. The increased levels of malondialdehyde and nitric oxide level were significantly decreased by morin (20 and 40 mg/kg) treatment. Also, reduced levels of superoxide dismutase and glutathione were increased significantly by morin treatment. Conclusions: Results of the present study indicate that morin showed its anti-convulsant effect via modulating the levels of brain GABA, Na+K+ATPase, and oxido-nitrosative stress. Thus, morin can be a potential candidate for further clinical evaluations as an anti-epileptic agent.

Potentiation of GABAA receptor activity by volatile anaesthetics is reduced by α5GABAA receptor-preferring inverse agonists.

BACKGROUND: Animal studies have shown that memory deficits in the early post-anaesthetic period can be prevented by pre-treatment with an inverse agonist that preferentially inhibits α5 subunit-containing γ-aminobutyric acid type A (α5GABA(A)) receptors. The goal of this in vitro study was to determine whether inverse agonists that inhibit α5GABA(A) receptors reduce anaesthetic potentiation of GABAA receptor activity. METHODS: Cultures of hippocampal neurones were prepared from Swiss white mice, wild-type mice (genetic background C57BL/6J and Sv129Ev) and α5GABA(A)receptor null mutant (Gabra5-/-) mice. Whole-cell voltage clamp techniques were used to study the effects of the α5GABA(A) receptor-preferring inverse agonists L-655,708 and MRK-016 on anaesthetic potentiation of GABA-evoked currents. RESULTS: L-655,708 (50 nM) reduced sevoflurane potentiation of GABA-evoked current in wild-type neurones but not Gabra5-/- neurones, and produced a rightward shift in the sevoflurane concentration-response plot [sevoflurane EC50: 1.9 (0.1) mM; sevoflurane+L-655,708 EC(50): 2.4 (0.2) mM, P<0.05]. Similarly, L-655,708 (50 nM) reduced isoflurane potentiation of GABA-evoked current [isoflurane: 4.0 (0.6) pA pF(-1); isoflurane+L-655,708: 3.1 (0.5) pA pF(-1), P<0.01]. MRK-016 also reduced sevoflurane and isoflurane enhancement of GABA-evoked current [sevoflurane: 1.5 (0.1) pA pF(-1); sevoflurane+MRK-016 (10 nM): 1.2 (0.1) pA pF(-1), P<0.05; isoflurane: 3.5 (0.3) pA pF(-1); isoflurane+MRK-016 (1 nM): 2.9 (0.2) pA pF(-1), P<0.05]. CONCLUSIONS: L-655,708 and MRK-016 reduced the potentiation by inhaled anaesthetics of GABAA receptor activated by a low concentration of GABA. Future studies are required to determine whether this effect contributes to the memory preserving properties of inverse agonists after anaesthesia.

General anaesthetics do not impair developmental expression of the KCC2 potassium-chloride cotransporter in neonatal rats during the brain growth spurt.

BACKGROUND: The developmental transition from depolarizing to hyperpolarizing γ-aminobutyric acid-mediated neurotransmission is primarily mediated by an increase in the amount of the potassium-chloride cotransporter KCC2 during early postnatal life. However, it is not known whether early neuronal activity plays a modulatory role in the expression of total KCC2 mRNA and protein in the immature brain. As general anaesthetics are powerful modulators of neuronal activity, the purpose of this study was to explore how these drugs affect KCC2 expression during the brain growth spurt. METHODS: Wistar rat pups were exposed to either a single dose or 6 h of midazolam, propofol, or ketamine anaesthesia at postnatal days 0, 5, 10, or 15. KCC2 expression was assessed using immunoblotting, immunohistochemistry, or quantitative polymerase chain reaction analysis up to 3 days post-exposure in the medial prefrontal cortex. RESULTS: There was a progressive and steep increase in the expression of KCC2 between birth and 2 weeks of age. Exposure to midazolam, propofol, or ketamine up to 6 h at any investigated stages of the brain growth spurt did not influence the expression of this cotransporter protein. CONCLUSION: I.V. general anaesthetics do not seem to influence developmental expression of KCC2 during the brain growth spurt.

Antiepileptic activity of lobeline isolated from the leaf of Lobelia nicotianaefolia and its effect on brain GABA level in mice.

OBJECTIVE: To investigate the anticonvulsant activity of the lobeline isolated from the Lobelia nicotianaefolia in chemoconvulsant-induced seizures and its biochemical mechanism by investigating relationship between seizure activities and altered gamma amino butyric acid (GABA) in brain of mice in Pentylenetetrazol (PTZ) seizure models. METHODS: The anticonvulsant activity of the isolated lobeline (5, 10, 20 and 30 mg/kg, i.p.) was investigated in PTZ and strychnine induced seizures in mice and the effect of isolated lobeline on brain GABA level in seizures induced by PTZ. Diazepam was used as reference anticonvulsant drugs for comparison. RESULTS: Isolated lobeline (10, 20 and 30 mg/kg, i.p.) significantly delayed and antagonized (P < 0.050-0.001) the onset of PTZ-induced seizures. It also antagonized strychnine induced seizures. The mortality was also prevented in the test group of animals. In biochemical evaluation, isolated lobeline (5, 10 and 20 mg/kg, i.p.) significantly increased the brain GABA level. And at dose of 30 mg/kg GABA level showed slight decrease in PTZ model. CONCLUSIONS: In our findings, isolated lobeline (20mg/kg) exhibited potent anticonvulsant activity against PTZ induced seizures. Also a biochemical evaluation suggested significant increase in barain GABA level at 20 mg/kg i.p. of isolated lobeline. Hence, we may propose that lobeline reduces epileptic seizures by enhancing the GABA release supporting the GABAergic mechanism.