effects of nigella sativa hydro-alcoholic extract on memory and brain tissues oxidative damage after repeated seizures in rats

Regarding the therapeutic properties of Nigella sativa [NS], the effects of the plant hydro–alcoholic extract on learning, memory and brain tissues oxidative damage were investigated in penthylenetetrazole [PTZ]-induced repeated seizures. There were 4 experimental groups including: 1- control group; received saline, 2- PTZ group; received saline and PTZ [50 mg/Kg, i.p], 3- PTZ-NS 200 and 4- PTZ-NS 400 ; received 200 and 400 mg/Kg of NS extract respectively, before PTZ injection in 5 consecutive days. Seizure scores were lower in PTZ–NS 200 and 400, furthermore the seizure onset latencies were higher in these groups than PTZ group [P<0.05 and P<0.01]. In Morris water maze, the time spent in target quadrant by PTZ group was lower than control group [P<0.05]; while, 400 mg/Kg of the extract increased it [P<0.01]. In the passive avoidance test, delay time to enter the dark by PTZ group was lower than control at 1 and 24 hours after training [P<0.01 - P<0.001]; while, 400 mg/Kg of the extract increased it [P<0.05]. The total thiol concentration in hippocampal and cortical tissues of PTZ group was reduced while, MDA concentration was higher than control [p<0.05 - p<0.001]. Administration of the extract increased the total thiol and decreased the MDA concentrations [p<0.01 - p<0.001]. It is concluded that the hydro-alcoholic extract of NS possess beneficial effects on learning and memory impairments in repeated seizures model which is accompanied by antioxidant effects in the brain

Chronic treatment by L-nAME differently affects morris water maze tasks in ovariectomized and naive female rats

Introduction: The role of ovarian hormones and nitric oxide [NO] in learning and memory and their interaction has been widely investigated. The present study carried out to evaluate different effect of L-NAME on spatial learning and memory of ovariectomized [OVX] and sham operated rats. Methods: 32 rats were divided into 4 groups: 1] Sham; 2] OVX; 3] Sham-LN; and 4] OVX-LN. The animals of groups 3 and 4 were treated by L-NAME [10 mg/kg/ day] for 8 weeks while the animals of groups 1 and 2 received saline [1ml/kg/day] instead of L-NAME. The animals of all groups were then tested in Morris water maze during five days. The escape latency and traveled distance were compared between groups. Results: Distance and time in OVX group was significantly higher than Sham group [p<0.01 and p<0.05]. Time and distance in Sham-LN group was higher in comparison with Sham group [p<0.05 and p<0.01]. There were no significant differences between OVX-LN and OVX groups in escape latency and traveled distance. Discussion: The results of present study showed that removal of ovarian hormones could impair Morris water maze tskas includiong time and distance. Administarion of non specific nitricoxide inhibitor, L-NAME, affects Morrsi water maze tasks however, its effect is different in the absence and presence of ovarian hormones but it needs to be more investigated