Biomedical subjects

N Pitsikas

Publications and source records attributed to N Pitsikas.

24 records · Page 2Linked to original sources

PubMedDate not supplied

The ACTH/MSH (4-9) analog Org2766 improves retrieval of information after a fimbria fornix transection.

The fimbria fornix of male Wistar rats was transected unilaterally after they had been successfully trained in the Morris maze and the passive avoidance task. Sham-operated and lesioned animals were treated either with Org2766 or saline for two weeks. Subsequently, the performance of all groups was tested again starting two days after the last treatment. The lesioned animals showed a deficit in performance in both tasks, indicating interference of the lesion with retrieval of information. Org2766 improved the poor performance of the lesioned animals in the Morris maze, but not in the passive avoidance task.

Adrenocorticotropic Hormone↗

PubMedDate not supplied

Effect of life-long hypocaloric diet on age-related changes in motor and cognitive behavior in a rat population.

Aged (24 months), adult (12 months), and young (4 months) rats kept on standard or hypocaloric diets from the age of three weeks old were tested in a range of behavioral tests to determine the effects of aging on sensory-motor and cognitive behavior and to assess whether such effects were prevented by life-long calorie restriction. An age-related deterioration of sensory-motor functions, motility and exploratory activity was observed in all the senescent animals independent of diet. Swimming ability did not deteriorate with age. Spatial memory, evaluated by the Morris water maze test, showed some deterioration in normally fed adult rats as indicated by the deceleration in the learning curve. In aged rats, not only was learning slowed down, but memory utilization was also impaired. These cognitive deficiencies were absent in rats fed the hypocaloric diet.

Aging↗

PubMedDate not supplied

Age-related ability of rats kept on a life-long hypocaloric diet in a spatial memory test. Longitudinal observations.

Cognitive behavior was assessed in a test specific for spatial memory, according to a longitudinal experimental model, in populations of 12-, 24- and 30-month-old rats which were fed ad lib either a standard (ST) or a hypocaloric (HY) diet, that had been shown to reduce age-related pathologies and to increase survival. Already at 12 months of age, some cognitive deficits were observed in ST but not in HY rats. When retested 12 and 18 months later, the animals performed better at the beginning of the test than when tested for the first time, indicating that some aspects of previous experience lead to a preservation of spatial memory. Deficits which had been previously observed in 2-year-old groups in a cross-sectional experimental model were not evident this time. Some of the differences between the two diet groups observed 12 months before disappeared. When testing was repeated for the third time at 30 months of age, ST fed rats presented very marked deficits in learning and in memory, which were not seen in the HY group. It thus appears that a dietary regimen in which part of the calorie-rich components, such as lipids and carbohydrates, are replaced with vegetable fibers, retards some of the age-related deteriorations of brain functions.

Aging↗

PubMedDate not supplied

Aging and food restriction: effect on lipids of cerebral cortex.

In experimental animals dietary restriction reduces the body weight increase due to aging, increases longevity and delays the onset of age-related physiological deterioration, including age-related changes in serum lipids. Little is known about the influence of food restriction on brain lipids, whose concentration and composition have been shown to change with age. We studied whether some biochemical and biophysical parameters of rat brain membranes, known to be modified with age, were affected by a diet low in calories, in which 50% of lipids and 35% of carbohydrates have been replaced by fibers. The diet was started at weaning and maintained throughout the animal's entire life span. Animals fed the low calorie diet survived longer and gained less body weight than standard diet fed rats. Age-related increases in microviscosity, cholesterol/phospholipid and sphingomyelin/phosphatidylcholine ratios were reduced or restored to the levels of young animals in cortex membranes of 32 old rats fed the low calorie diet, while the age-related increase in mono- to polyunsaturated fatty acid ratios in phospholipids was further raised. In conclusion we have shown that a diet low in calories and high in fibers affects lipid composition in the rat brain, in a direction opposite to that normally believed to reduce age-related deterioration of brain functions.

Aging↗

PubMedDate not supplied

Deterioration of spatial and nonspatial reference and working memory in aged rats: protective effect of life-long calorie restriction.

Two different aspects of learning (spatial and nonspatial) and two different types of memory (reference and working) were simultaneously measured in populations of 3- (young), 11- (adult), and 25-month-old (aged) rats fed ad libitum either a standard (ST) or a hypocaloric (HY) diet. All groups, regardless of age or diet, showed ability in learning all four versions of the task. However, old ST rats were significantly slower and less efficient at learning than the young and adult ST rats. In contrast, senescent HY rats' cognitive abilities did not differ from those of their young and adult counterparts. The decline in reference and working memory in the aged ST rats was more pronounced in the spatial than the nonspatial version of the task. This study confirms and extends to more specific aspects of memory our earlier finding that age-related cognitive deterioration in rats was antagonized by life-long calorie restriction.

Aging↗

PubMedDate not supplied

DAU 6215, a novel 5-HT3 receptor antagonist, improves performance in the aged rat in the Morris water maze task.

The effects of the new 5-HT3 receptor antagonist, DAU 6215, on aged rats' cognition were assessed in the Morris water maze task. Task performance of aged animals that received acutely the dose of 10 micrograms/kg IP was not different than that of their aged controls treated with the vehicle. Conversely, a repeated IP administration of 10 micrograms/kg DAU 6215 for 3 weeks significantly improved task performance of the aged animals as compared to that displayed by the old rats treated with the vehicle.

Aging↗