To study the different effects of soy extract on pentylenetetrazole (PTZ)-induced seizures in the presence and absence of ovarian hormones in rats, and the gender-dependent differences in the effects of phytoestrogens on behavior.

Objective: To investigate the effects of soy extract on pentylenetetrazol (PTZ)-induced seizures in ovariectomized (OVX) rats. Methods: Female Wistar rats were randomly divided into 4 groups (n=15 in each group) as follows: sham-operated, OVX, low-dose soy (LDS) and high-dose soy (HDS). The rats in each group were divided into two subgroups and received daily injection of a low dose of PTZ (40 mg/kg body weight, intraperitoneally, n=7 in each subgroup) for 14 d or a single injection of a high dose of PTZ (90 mg/kg body weight, intraperitoneally, n=8 in each subgroup). The rats of LDS and HDS groups were injected with 20 and 60 mg/kg body weight of soy extract intraperitoneally, respectively, just 30 min before each PTZ injection. The rats of the sham-operated and the OVX groups received saline instead of soy extract. After treatment, the rats were placed in a plexiglas cage and their behaviors were observed for 60 min. Results: The results of repeated injection of low dose of PTZ during 14 d showed that the seizure score of the rats of OVX group on days 3, 5, 8, 10, 11, 12, and 13 was lower than that of the sham-operated group (P<0.05 or P<0.01). However, the rats of both LDS and HDS groups had higher score compared with the OVX group on the mentioned days (P<0.05 or P<0.01). The results of a single injection of a high dose of PTZ showed a significant increase (P<0.01) in the generalized tonic-clonic seizure (GTCS), but not the minimal clonic seizure (MCS) in the OVX rats compared with the sham-operated rats. Treatment with both low and high doses of soy extract significantly decreased the GTCS and MCS latencies compared with the OVX group (P<0.01). Conclusion: Female hormones affect seizure severity induced by PTZ, and phytoestrogens of soy mimic this effects. However, more investigations need to be done in the future.

OBJECTIVETo evaluate the effect of Nigella sativa (NS) extract on memory performance and its possible mechanisms in scopolamine (Sco)-induced spatial memory impairment model using Morris water maze test.

METHODSThirty-two male Wistar rats were randomly divided into four groups. The control group received saline instead of both NS extract and Sco. The Sco group was treated by saline for two weeks, and was injected by Sco (2 mg/kg, intraperitoneally) 30 min before each trail in Morris water maze test. Sco+NS 200 and Sco+NS 400 groups were daily treated by 200 or 400 mg/kg of NS (intraperitoneally) for two weeks, respectively, and were finally injected by Sco 30 min before Morris water maze test. The brains of animals were removed to determine the acetylcholinesterase (AChE) activity and oxidative stress criteria in cortical tissues.

RESULTSTime latency and path length in the Sco group were significantly higher than in the control group (P<0.01), while the Sco+NS 400 group showed a significantly shorter traveled path length and time latency compared with the Sco group (P<0.01). AChE activity in the cortical tissues of the Sco group was significantly higher than the control group (P<0.01), while AChE activity in the Sco+NS 200 and Sco+NS 400 groups was lower than the Sco group (P<0.01). Following Sco administration, malondialdehyde (MDA) concentrations were increased (P<0.01) in comparison with the control group, while cortical total thiol content decreased (P<0.01). Pretreatment with extracts caused a significant elevation in cortical total thiol content (P<0.01) and reduction in cortical MDA concentration (P<0.01) compared with the Sco group.

CONCLUSIONSHydro-alcoholic extract of NS prevents Sco-induced spatial memory deficits and decreases the AChE activity as well as oxidative stress of brain tissues in rats. Our results support the traditional belief about the beneficial effects of NS in nervous system. Moreover, further investigations are needed for better understanding of this protective effect.

Acetylcholinesterase ; metabolism ; Animals ; Ethanol ; chemistry ; Male ; Malondialdehyde ; metabolism ; Maze Learning ; drug effects ; Memory Disorders ; drug therapy ; physiopathology ; Nigella sativa ; chemistry ; Plant Extracts ; pharmacology ; therapeutic use ; Rats, Wistar ; Reaction Time ; drug effects ; Scopolamine Hydrobromide ; Spatial Memory ; drug effects ; Sulfhydryl Compounds ; metabolism ; Water ; chemistry