Retention Of Conditioned Avoidance Response Research Articles

The study of effects of inhibition of the renin angiotensin system on memory in rats

Background: The existence of an independent renin angiotensin aldosterone system (RAAS) has been well-established and is known to modulate various pathological processes such as neuroinflammation, neurodegeneration, and neural injury, in addition to the RAAS in the cardiovascular system.Methods: Eighteen Wistar rats were divided into 3 study groups (n=6; Losartan, Ramipril, Normal Saline), trained on the Cook’s Pole climbing apparatus till the conditioned avoidance response (CAR) rate was 100%. The retention of CAR was tested each week for 4 consecutive weeks. The number of times that the animal successfully avoided the shock, and the time taken for this avoidance were measured and compared with placebo (Normal Saline). The values have been expressed as Mean±Standard Deviation (SD). A p-value of less than 0.05 has been considered as significant.Results: The retention of the conditioned avoidance response in the group receiving study drugs was significantly more than the placebo group. However, there was no show significant difference between Losartan and Ramipril in the rate of retention, or the time taken for avoidance.Conclusions: In this study, Ramipril and Losartan have a beneficial effect on learning and memory as compared to plcebo.

A comparative study of American ginseng (spp. Panax quinquefolius) and Donepezil on working memory in rats using scopolamine induced disruption of memory

Background: Treatment of Alzheimer’s disease (AD) includes acetylcholinesterase inhibitors like Donepezil. American ginseng has been postulated to enhance learning and memory owing to its antiapoptotic activity as well as inhibition of formation of β amyloid plaque. Scarce data is available on effect of combination of these two drugs. Hence, we have conducted this study to evaluate the same. Aim and objectives of the study were to evaluate the role of American ginseng on working memory in rats and to compare the effect of American ginseng with Donepezil on working memory in rats.Methods: Sprague-Dawley rats of either sex, weighing 150-200g were used and obtained from animal house of Dr. D. Y. Patil Medical College, Hospital and Research Centre, Pimpri, Pune. To study the effects of the drugs on working memory in rats, they were trained for conditioned avoidance response (CAR) using Cook's pole climbing apparatus. The method of Fellow and Cook was used.Results: In the group C (i.e. the control group), 50% of rats showed the retention of CAR. In the group S (i.e. only scopolamine group), only 20% of rats showed the retention of CAR. In the group S+AG (i.e. scopolamine and American ginseng), 60% of rats showed the retention of CAR. In the group S+ D (i.e. scopolamine and Donepezil) 70% of rats showed retention of CAR. In the group S+D+AG (i.e. the combination group of scopolamine, Donepezil and American ginseng), 80% of rats showed the retention of CAR.Conclusions: From this study we can conclude that American ginseng and Donepezil have comparable effects in retention of working memory. The combination of American ginseng and Donepezil can have additive effect on the retention of working memory.

Evaluation of nootropic and neuroprotective effects of low dose aspirin in rats

Objective:To evaluate the nootropic and neuroprotective effects of aspirin in Sprague Dawley rats.Materials and Methods:Retention of conditioned avoidance response (CAR) and central 5-HT-mediated behavior (lithium-induced head twitches) were assessed using repeated electroconvulsive shock (ECS) in rats. Rats were divided into eight groups: control (pretreated with distilled water), scopolamine (0.5 mg/kg i.p.), ECS (150 V, 50 Hz sinusoidal with intensity of 210 mA for 0.5 s) pretreated, aspirin (6.75 mg/kg orally) pretreated, combined scopolamine and aspirin pretreated, ondansetron (0.36 mg/kg orally) pretreated, combined ECS and ondansetron pretreated and combined ECS and aspirin pretreated groups. Data was analyzed by the chi-square test and ANOVA.Results:Findings show that administration of single ECS daily for consecutive 8 days results in enhancement of 5-HT-mediated behavior (lithium-induced head twitches) and in disruption of the retention of CAR. Aspirin and ondansetron administration significantly increased the retention of conditioned avoidance response compared to control. Ondansetron and aspirin significantly prevented ECS-induced attenuation of the retention of conditioned avoidance response also. On the other hand, ondansetron and aspirin significantly retarded the ECS-induced enhancement of 5-HT-mediated behavior.Conclusion:Inhibition of the serotonergic transmission by aspirin is responsible for its nootropic and neuroprotective actions.

The effects of telencephalic pallial lesions on spatial, temporal, and emotional learning in goldfish

In mammals, the pallial amygdala is implicated in emotional learning and memory, whereas the hippocampus is involved in spatial, contextual, or relational memory. This review presents a set of experiments aimed to study the involvement of the dorsomedial and dorsolateral telencephalon of goldfish in spatial and active avoidance learning. Results showed that (1) medial lesions impaired both acquisition and retention of conditioned avoidance response in two-way active avoidance learning experiments with stimuli overlapping (emotional factor) and with an interstimuli gap (temporal and emotional factors), and (2) the medial lesion did not affect spatial learning (spatial, contextual, or relational factors). In contrast, lateral lesions did not impair conditioned avoidance response with stimuli overlapping, but affected conditioned avoidance response with an interstimuli gap and spatial learning. These results support the presence of two differentiated memory systems in teleost fish based on discrete pallial regions: emotional (dorsomedial telencephalon) and spatial/temporal or relational (dorsolateral telencephalon). Furthermore, these functional data support the homology between the medial pallium of the teleost and the pallial amygdala of land vertebrates, and between the teleost lateral pallium and the mammalian hippocampus.

Inhibition of catecholamine biosynthesis and memory processes

Rats injected with 60 mg/kg of alpha-methyl tyrosine (alpha-MT) immediately after a training in a shuttle box impaired retention of conditioned avoidance response (CAR). DL-Dopa (200 mg/kg) administered 5, 30, 60, and 120 min after alpha-MT treatment counteracted the depressive effect of this drug during the retention test; at longer times it was ineffective. Post-trial injections of 600 mg/kg of diethyldithiocarbamate (DDC) impaired retention of CAR; at a lower dose (300 mg/kg) it had no effect. Administration of alpha-MT (60 mg/kg) immediately after passive avoidance training lowered memory in females but not in males. These results suggest that noradrenaline (NA) is required for memory consolidation processes for about 2 h after training.

Striate cortex ablation and deficits in conditioned avoidance response

Cats were tested for acquisition and retention of conditioned avoidance response to an auditory CS following ablation of a portion of striate cortex and were found to be significantly deficient compared with normals. Blinding normal or operated cats with opaque contact lenses also caused a significant deficit in acquisition and retention of the CAR. Combination of striate cortex ablation and blinding by contact lenses prevented avoidance responses in four of ten operated cats. The marked deficit in an auditory task in the absence of visual cues suggests a complexity of effect of striate ablation not explainable only in terms of visual loss.