Memory retention in old rats: improvement by orotic acid

The Combination Effects of Resveratrol and Swimming HIIT Exercise on Novel Object Recognition and Open-field Tasks in Aged Rats

INTRODUCTION

Resveratrol, a natural polyphenol abundant in grapes and red wine, has been reported to exert numerous beneficial health effects in the body. High-Intensity Interval Exercise (HIIT) is a form of interval training that provides improved athletic capacity and has a protective effect on health. The purpose of this study was to investigate the interactive effects of swimming HIIT and Resveratrol supplementation on behavioral function in Novel object recognition and open-field tests in aged rats.

METHODS

A total of 45 aged male Wistar rats with an age of 20 months were randomly assigned into five groups of control (C), swimming HIIT (SW-HIIT), swimming HIIT with Resveratrol supplementation (SW-HIIT-R), Resveratrol supplementation (R), and solvent of Resveratrol supplementation (SR). There was also another group that included young animals (2-month-old) and was used to compare with older animals. Swimming HIIT and Resveratrol supplementation groups performed the exercise and received Resveratrol (10 mg/kg/day, gavage) for six weeks. Novel object recognition and open-field tests were used for evaluating the behavioral functions in animals.

RESULTS

The results showed that HIIT and Resveratrol significantly improved recognition memory compared to old animals. Moreover, it seems that HIIT and Resveratrol partly could modulate anxiety-like behaviors compared to old animals in the open-field test.

Metabolic effect of orotic acid in calves

Eight calves (males, Black and White crossbred with Holstein-Fresian) were fed milk and milk replacer without (control group) or with potassium orotate (3 mmol./l.) supplementation for 6 weeks after birth. Orotate depressed the biosynthesis of polyamines in mucosa of the gastrointestinal tract (rumen, omasum, abomasum, colon) by decreasing of ornithine decarboxylase activity with a simultaneous compensatory increase of S-adenosyl-methionine decarboxylase activity. A lower concentration of spermidine and spermine in the mucosa of the colon was also noted. The above changes were accompanied by increased urinary excretion of ornithine and arginine. Calf adaptation to a high OA intake was associated with an increased activity of the OA metabolizing enzyme complex (orotate phosphoribosyl transferase and orotidine monophosphate decarboxylase) in the liver, while urinary OA losses diminished with age. Increased concentrations of uracil and uridine in the liver and higher urinary excretion of pseudouridine in OA-fed calves was also observed. Stimulation of pyrimidine metabolism by OA depressed purine synthesis, which was reflected by a decrease of urate, hypoxanthine, and xanthine concentration in the liver. Interestingly OA enhanced urate excretion by the kidneys. OA strongly affected lipid metabolism in calves because total cholesterol, LDL-, and HDL-cholesterol, and triglycerides in blood plasma decreased while triglycerides accumulated in the liver of OA-fed calves. Milk OA in concentrations characteristic of cows with hereditary orotic aciduria exerts an unfavourable effect on the metabolism of polyamines, purines, and lipids in calf tissues.

Orotate improves memory and enhances synaptic long-term potentiation in active avoidance behaviour in rats with perforant path stimulation as the conditioned stimulus

Male Wistar rats were trained in an active avoidance task with stimulation of the perforant path with impulse trains of 15 Hz as the conditioning stimulus. Immediately after the first training session, methylglucamine orotate (225 micrograms), a memory improving drug, was injected intraventricularly. The retention of the learned behaviour was determined on the following day in a relearning session. Field potentials evoked in the dentate area by test stimuli from the perforant path electrode were recorded at different times after learning and relearning sessions to determine whether there were functional changes in the perforant path-granular cell synapses, which are involved in the conditioning pathway. Untreated control animals exhibited a so-called 'postconditioning potentiation', expressed as a long-lasting increase of both the excitatory postsynaptic potential (EPSP) and the population spike of the granular cells of the evoked test potentials. This finding reproduces previously published results. Methylglucamine orotate-treated rats showed significantly more conditioned reactions in the relearning sessions compared with untreated controls and a significantly more pronounced potentiation of the population spike, whereas the postconditioning potentiation of the field EPSP remained unaffected by the treatment. When both the control animals and the methylglucamine orotate-treated rats were divided into subgroups of good and poor learners according to their learning scores from the first training session, differences between the effect of the drug became evident. In good learners, the treatment with methylglucamine orotate after the learning session slightly, but significantly, improved retention compared with that of untreated good learners.(ABSTRACT TRUNCATED AT 250 WORDS)