Age-related changes in the antinociception induced by taurine in mice

Effects of Caffeine and Caffeinated Beverages in Children, Adolescents and Young Adults: Short Review

The prevalence of ED consumption has increased over the past 10–15 years. Studies describing the effects of caffeine and caffeinated beverages show confusing results, so it seems important to regularly summarize the available facts, and in more detail. By a thorough analysis of more than 156 scientific papers, the authors describe the molecular background of absorption, as well as the positive and negative effects of different dosages of caffeine, just like its effects in physical activity and performance. ED and EDwA consumption is a regular habit of not only adults, but nowadays even of children and adolescents. There are no safe dosages described of caffeine or ED consumption for children. There are no positive short- or long-term effects of these compounds/products concerning developing brain functions, psycho-motor functions, or social development. Instead, there are many unpleasant side effects, and symptoms of regular or higher-dose ED consumption, especially at younger ages. This mini review describes many details of these unpleasant side effects, their severity, and motivations for consuming these compounds/products. In a quantitative research in Hungary (10–26 years, mean age: 15.6 ± 3.8 y, 1459 subjects, randomly chosen population), a survey based on a questionnaire asking people about their ED consumption habits was conducted. According to the data, 81.8% of the participants consumed EDs at least once, and 63.3% tried several products of the kind. A positive correlation was found between age and consumption (p < 0.001). The results show that a high proportion of this group often consumed EDwA, in many cases leading to harmful side-effects of caffeine overdose. In a sample of Hungarian high school and college students (17–26 years), ED consumption matched the international data, and only 19.7% of respondents did not use EDs at all (had never tasted an ED in their life).

Taurine, caffeine, and energy drinks: Reviewing the risks to the adolescent brain

Energy drinks are emerging as a major component of the beverage market with sales projected to top $60 billion globally in the next five years. Energy drinks contain a variety of ingredients, but many of the top-selling brands include high doses of caffeine and the amino acid taurine. Energy drink consumption by children has raised concerns, due to potential caffeine toxicity. An additional risk has been noted among college-aged consumers of energy drinks who appear at higher risk of over-consumption of alcohol when the two drinks are consumed together. The differential and combinatorial effects of caffeine and taurine on the developing brain are reviewed here with an emphasis on the adolescent brain, which is still maturing. Key data from animal studies are summarized to highlight both reported benefits and adverse effects reported following acute and chronic exposures. The data suggest that age is an important factor in both caffeine and taurine toxicity. Although the aged or diseased brain might benefit from taurine or caffeine supplementation, it appears that adolescents are not likely to benefit from supplementation and may, in fact, suffer ill effects from chronic ingestion of high doses. Additional work is needed though to address gaps in our understanding of how taurine affects females, since the majority of animal studies focused exclusively on male subjects.

Intracerebroventricular administration of taurine impairs learning and memory in rats

OBJECTIVES

Taurine is a semi-essential amino acid widely distributed in the body and we take in it from a wide range of nutritive-tonic drinks to improve health. To date, we have elucidated that oral supplementation of taurine does not affect learning and memory in the rat. However, there are few studies concerning the direct effects of taurine in the brain at the behavior level. In this study, we intracerebroventricularly administered taurine to rats and aimed to elucidate the acute effects on learning and memory using the Morris water maze method.

METHODS

Escape latency, swim distance, and distance to zone, which is the integral of the distance between the rats and the platform for every 0.16 seconds, were adopted as parameters of the ability of learning and memory. We also tried to evaluate the effect of intraperitoneal taurine administration.

RESULTS

Escape latency, swim distance, and distance to zone were significantly longer in the intracerebroventricularly taurine-administered rats than in the saline-administered rats. Mean swimming velocity was comparable between these two groups, although the physical performance was improved by taurine administration. Probe trials showed that the manner of the rats in finding the platform was comparable. In contrast, no significant differences were found between the intraperitoneally taurine-administered rats and the saline-administered rats.

DISCUSSION

These results indicate that taurine administered directly into the brain ventricle suppresses and delays the ability of learning and memory in rats. In contrast, it is implied that taurine administered peripherally was not involved in learning and memory.

Effects of taurine on rat behaviors in three anxiety models

In our previous studies using an elevated plus-maze test in mice, taurine was shown to present an anxiolytic-like effect after single and repeated administration. The aim of the present study was to investigate the anxiolytic and behavioral effects of taurine on rats in the open field, hole-board, and social interaction test compared to the positive control diazepam. Taurine (14, 42, and 126 mg/kg, i.p.) was administered 30 min before the tests. In the social interaction and hole-board tests, taurine (42 mg/kg) significantly increased social interaction time and the number and duration of head-dipping. In the open field test, taurine (126 mg/kg, i.p.) presented anxiolytic-like effects by increasing the number of center entries, time spent in the central area and the anti-thigmotactic score while having no effect on the locomotor activity. Results from these experiments suggest that taurine produces an anxiolytic-like effect in these animal models and may act as a modulator or anti-anxiety agent in the central nervous system.