Study on the anticonvusant activity of thymoquinone, the major constituent of Nigella Sativa L.seeds, through intracerebroventricular injection

Thymoquinone, the major constituent of Nigella sativa seeds, is a biologically active compound, which possesses several pharmacological effects. The aim of the present study was to evaluate the anticonvulsant effect of thymoquinone through intracerebroventricular [i.c.v.] injection. The anticonvulsant effects of thymoquinone, the major constituent of Nigella sativa seeds, were investigated using pentylenetetrazole [PTZ]-induced seizure model. In PTZ-induced epileptic seizures, the i.c.v. injection of thymoquinone [200 and 400 mol] prolonged the onset and reduced the duration of tonic-clonic seizures. The protective effect of thymoquinone against lethality was 45% and 50% in the mentioned doses, respectively. In this study, flumazenil [1 nmol, i.c.v.] reversed the anticonvulsant activity of thymoquinone. Also, pretreatment with naloxone [10 mol, i.c.v.] antagonized the prolongation of tonic-clonic seizure latency, as well as reduction in seizure duration both induced by thymoquinone [200 mol, i.c.v.]. These results indicate that thymoquinone may possess anticonvulsant activity probably through an opioid receptor-mediated increase in GABAergic tone

effects of carbenoxolone, a gap junction channel blocker, on spatial learning inMorris water maze task in rats

High frequency oscillations [ripples] are proposed to involve in memory consolidation. Ripple oscillations persist in the absence of chemical synaptic transmission and inhibitors of gap junctions were shown to block high frequency oscillations in hippocampal slices. In this study, we investigated the effects of carbenoxolone, as a gap junction blocker, on spatial learning in the rat. Cognitive performance was assessed using Morris water maze [MWM]. Adult male rats were bilaterally cannulated into the CA1 region of their hippocampus. Carbenoxolone [1.23, 2.46, 4.92 microg/side], scopolamine [microg/side] and saline were injected through the cannulas before training for 4 consecutive trials and one probe trial that was conducted 24 h after the training trials with the platform removed. The results showed that carbenoxolone could significantly reduced percent of time spent, distance traveled and quadrant entry in Q2 compared to control group and failed to use a selective search strategy during probe trial in which the platform was removed.The results of the present study suggest that carbenoxolone as a gap junction channels blocker can decelerate learning performances of rats in a spatial memory task such as the MWM that requires the integrity of hippocampus