An Assessment of Taurine as a Nootropic in aged male rats in the attention set-shift test

Abstract

The global population is continuing to age more than ever before, while at the same time increasing the rates of age-related cognitive dementias and associated neurodegenerative disorders. This situation has directed researchers to examine the potential for cognitive enhancing drugs to ameliorate or forestall the naturally occurring age-dependent decline in cognitive functions that accompanying aging. The present study examined in aged male rats (i.e., 1-year of age) that were randomly assigned to either a Control water of 0.05% Taurine water (i.e., for 1-month) prior to being subjected to the Attention Set-Shift Test (ASST; a very sensitive test for cognitive functions of the frontal lobes, flexibility, and evaluation of perseverative behaviors). The Control rats unfortunately with age could not form the necessary simple and complex discriminations to complete the ASST and failed the test. Interestingly, the age-matched Control+Taurine rats were able to complete the ASST and did so at rates comparable to younger (i.e., 60 day old) rats. Then as an additional proof of concept, the Control rats that failed the test, half remained on the same treatment, whereas the other half were then switched to 0.05% Taurine water for 1-month. Another month later, the rats were re-tested and again the Control+Taurine rats were able to complete the ASST, but the Control rats could not. This study offers a first report of Taurine clearly serving as a nootropic (i.e., cognitive enhancing drug) in an aging model. It is thought that since aging reduces the level of GABA (i.e., the main inhibitory neurotransmitter in the brain), that taurine may serve to compensate and replenish levels of this neurotransmission which could explain the cognitive improvements in this animal model of aging. This work shows that taurine may prove to be an effective nootropic to be prescribed in aging populations to preserve cognitive functions in the elderly.