curcumin and Learning-Disabilities

Previous studies have shown that seizures can cause cognitive disorders. On the other hand, the Curcuma zedoaria (CZ) has beneficial effects on the nervous system. However, there is little information on the possible effects of the CZ extract on seizures. The aim of this study was to investigate the possible effects of CZ extract on cognitive impairment and oxidative stress induced by epilepsy in rats.. Rats were randomly divided into different groups. In all rats (except the sham group), kindling was performed by intraperitoneal injection of pentylenetetrazol (PTZ) at a dose of 35 mg/kg every 48 h for 14 days. Positive group received 2 mg/kg diazepam + PTZ; treatment groups received 100, 200 or 400 mg/kg CZ extract + PTZ; and one group received 0.5 mg/kg flumazenil and CZ extract + PTZ. Shuttle box and Morris Water Maze tests were used to measure memory and learning. On the last day of treatments PTZ injection was at dose of 60 mg/kg, tonic seizure threshold and mortality rate were recorded in each group. After deep anesthesia, blood was drawn from the rats' hearts and the hippocampus of all rats was removed.. Statistical analysis of the data showed that the CZ extract significantly increased the tonic seizure threshold and reduced the pentylenetetrazol-induced mortality and the extract dose of 400 mg/kg was selected as the most effective dose compared to the other doses. It was also found that flumazenil (a GABA. It is concluded that the CZ extract has beneficial effects on learning and memory impairment in PTZ-induced epilepsy model, which has been associated with antioxidant effects in the brain or possibly exerts its effects through the GABAergic system.

Topics: Animals; Anticonvulsants; Antioxidants; Brain Chemistry; Convulsants; Curcuma; Flumazenil; GABA Modulators; Learning Disabilities; Male; Malondialdehyde; Maze Learning; Memory Disorders; Nitric Oxide; Oxidative Stress; Pentylenetetrazole; Plant Extracts; Rats; Rats, Wistar; Seizures

Chronic stress occurs in everyday life and induces impaired spatial cognition, neuroendocrine and plasticity abnormalities. A potential therapeutic for these stress related disturbances is curcumin, derived from the curry spice turmeric. Previously we demonstrated that curcumin reversed the chronic stress-induced behavioral deficits in escape from an aversive stimulus, however the mechanism behind its beneficial effects on stress-induced learning defects and associated pathologies are unknown. This study investigated the effects of curcumin on restraint stress-induced spatial learning and memory dysfunction in a water maze task and on measures related neuroendocrine and plasticity changes. The results showed that memory deficits were reversed with curcumin in a dose dependent manner, as were stress-induced increases in serum corticosterone levels. These effects were similar to positive antidepressant imipramine. Additionally, curcumin prevented adverse changes in the dendritic morphology of CA3 pyramidal neurons in the hippocampus, as assessed by the changes in branch points and dendritic length. In primary hippocampal neurons it was shown that curcumin or imipramine protected hippocampal neurons against corticosterone-induced toxicity. Furthermore, the portion of calcium/calmodulin kinase II (CaMKII) that is activated (phosphorylated CaMKII, pCaMKII), and the glutamate receptor sub-type (NMDA(2B)) expressions were increased in the presence of corticosterone. These effects were also blocked by curcumin or imipramine treatment. Thus, curcumin may be an effective therapeutic for learning and memory disturbances as was seen within these stress models, and its neuroprotective effect was mediated in part by normalizing the corticosterone response, resulting in down-regulating of the pCaMKII and glutamate receptor levels.

Topics: Animals; Antidepressive Agents, Tricyclic; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Cells, Cultured; Cognition Disorders; Corticosterone; Curcumin; Hippocampus; Imipramine; Learning Disabilities; Male; Maze Learning; Memory Disorders; Neuronal Plasticity; Neuroprotective Agents; Pyramidal Cells; Random Allocation; Rats; Rats, Sprague-Dawley; Receptors, N-Methyl-D-Aspartate; Space Perception; Stress, Psychological