No abstract

Increased serum insulin levels and reduced peripheral insulin activities seen in insulin resistance syndrome are associated with age-dependent cognitive impairment and Sporadic Alzheimer's Disease (SAD), suggesting a disturbance in the insulin signalling system in the brain and possibly being one of the causes of dementia. Therefore, the streptozotocin (STZ)-induced animal may be an appropriate model for the investigation of SAD and related dementia. This study was designed to investigate the beneficial effect of Curcumin (CUR), a neuroprotective agent, on intracerebroventricular (ICV) STZ-induced cognitive impairment in rats. For this purpose, adult male Wistar rats were bilaterally ICV injected with STZ (3 mg/kg). An artificial cerebrospinal fluid (aCSF) was given to the control group (SHAM) instead of STZ on days 1 and 3. Learning and memory performance were assessed using the "passive avoidance task" and the "Morris water maze test". After confirmation of acquisition impairment with these tests, the STZ group was divided into two subgroups: STZ+ vehicle (Vh) and STZ+CUR. The rats in the SHAM and STZ+Vh groups were administered intraperitoneally with 0.5 ml Vh and the rats in the STZ+CUR group were treated intraperitoneally with CUR (300 mg kg −1 day −1 in Vh) for 10 days starting from the 25th day after STZ injection. The Morris water maze test was reapplied on the 35th day after STZ injection and all of the rats were sacrificed on day 36 for quantitation of IGF-1 and for histopathological evaluation. Rats in the STZ+CUR group were found to have a higher performance in cognitive tests than rats in the STZ+Vh group (P<0.01). In parallel with the cognitive tests, IGF-1 levels were decreased in all of the STZ-injected groups (1.78±0.34) compared to the SHAM group (3.46±0.41). In contrast, CUR treatment significantly increased IGF-1 levels (P<0.001). The degree of neuronal loss decreased after CUR treatment compared to the SHAM group (P< 0.02). These results clearly indicate that CUR treatment is effective in reducing the cognitive impairment caused AGE

No abstract

Our results indicate some beneficial effects of PDE5 inhibitory drugs, especially tadalafil, on oxidative I/R injury in fetal rat brains.

Impulsive choice, a form of impulsivity, is associated with tobacco smoking in humans. Trait impulsivity may be a vulnerability factor for smoking, or smoking may lead to impulsive behaviors. We investigated the effects of 14-day nicotine exposure (6.32 mg/kg/day base, subcutaneous minipumps) and spontaneous nicotine withdrawal on impulsive choice in low impulsive (LI) and high impulsive (HI) rats. Impulsive choice was measured in the delayed reward task in which rats choose between a small immediate reward and a large delayed reward. HI and LI rats were selected from the highest and lowest quartiles of the group before exposure to nicotine. In non-selected rats, nicotine or nicotine withdrawal had no effect on impulsive choice. In LI rats, chronic nicotine exposure decreased preference for the large reward with larger effects at longer delays indicating increased impulsive choice. Impulsive choices for the smaller immediate rewards continued to be increased during nicotine withdrawal in LI rats. In HI rats, nicotine exposure and nicotine withdrawal had no effect on impulsive choice, although there was a tendency for decreased preference for the large reward at short delays. These results indicate that nicotine- and nicotine withdrawal-induced increases in impulsive choice depend on trait impulsivity with more pronounced increases in impulsive choice in LI compared to HI subjects. Increased impulsivity during nicotine exposure may strengthen the addictive properties of nicotine and contribute to compulsive nicotine use.