Comparative Study of the Efficacy of L-Tryptophan Nanoparticles on Motor and Cognitive Behavior in an Alzheimer's Experimental Model

Abstract Alzheimer's disease is the most common neurodegenerative disorder, with cognitive as well as behavioral manifestations. Also related to this pathology, is the decreased production and activation of some neurotransmitters, such as Serotonin, which is derived from the Tryptophan. Different methods to improve the effect and performance of some drugs have been studied including the Nanoparticles. The objective was to analyze the efficacy of L-tryptophan and L-tryptophan Nanoparticles in the acute response of motor and cognitive behavior in an Alzheimer's experimental model. Methods: 15 Wistar rats, divided into 3 groups (n = 5): GC (Alzheimer's control group), GLt (L-tryptophan), and GN (Nanoparticles). They were treated for six consecutive days. Anxiety tests, spatial memory tests, aversive memory tests, and motor behavior tests were all performed during this study. In the analysis of anxiety, improvement was observed in both treatments, being that GN presented improvement in two variables: freezing (79±18.8; 74.6±14.2) and TBF (287.8±1.08; 268±40.8). GLt only presented improvement in freezing (103.8±44.4). In the spatial memory analysis, there were no significant differences in aversive memory and motor behavior during the treatments. During the Size Effect analysis treatments, it is possible to observe some differences both in anxiety and motor behavior, precisely where NG presented better results than GLt. Even in a short period of time, the nanoparticles demonstrated great benefits as a treatment method. Conclusion: the use of nanoparticles is an effective treatment against changes in motor and cognitive behavior caused by Alzheimer´s, as it lowers anxiety and improves motor behavior.