oa Editorial [Hot topic: Chemical Agents Positively and Negatively Affecting the Central Nervous System (Guest Editors: Abel Santamaria & Mauricio Diaz-Munoz)]

Science is progressing constantly, and this evolution is often difficult to follow if we consider the rapid and massive advance in every field of research. The study of molecules positively and negatively modulating the function of the Nervous System is not an exception. Recently, our knowledge on the actions that different chemical molecules exert modulating the Nervous System has been expanded with the help of a variety of molecular tools. In turn, these approaches have served to improve our understanding regarding how this System works, how vulnerable can be to the actions of neuroactive molecules, and by which mechanisms is affected, but mostly, how we can prevent or ameliorate some of its alterations through the design of therapeutic strategies based on chemical agents designed to either reduce or potentiate some functions in the brain. In this thematic issue of Central Nervous System Agents - Medicinal Chemistry, which is devoted to the general topic “Chemical Agents Positively and Negatively Affecting the Central Nervous System”, we have compiled the reviews of several colleagues with expertise in different themes related with the actions of chemical agents, either endogenous or exogenous, that modulate diverse functions of the Nervous System. These authors offer the state-of-the-art on their respective topics, thus bringing a valuable update to follow as referential works for all those colleagues doing biomedical and clinical research. First, Diaz- Munoz and Salin-Pascual make an updated approach to the role of agents such as adenosine, ATP and caffeine - all known purines - as hypnogenic factors and their relevance for future paradigms. Campos-Esparza and Torres-Ramos offer an interesting insight into the role of the antioxidant molecules, polyphenols, and their mechanisms of action in the brain. Tobon- Velasco and coworkers revisit the hard topic of Parkinson's disease and those molecules serving as biomarkers in this disorder and related animal models. Limon-Pacheco and Gonsebatt describe a compilation of evidence supporting a regulatory role of melatonin in the glutathione system in the Nervous System. Rubio and coworkers pay special attention to those molecules used up to date to produce experimental models of epilepsy under in vivo conditions. Aztatzi-Santillan and coworkers develop the topic of the protective properties of heme oxygenase-1 in cerebral ischemia with a molecular perspective. Following the issue of ischemia, Espinoza-Rojo and coworkers describe the relevance of glucose transporters as therapeutic targets by different modulators for possible treatment of this condition. Saenz and coworkers discuss the role of regulatory T cells and their chemical modulation in the Nervous System under different conditions. Finally, Montes de Oca-Balderas brings us an interesting approach to the regulated intracellular proteolysis and ectodomain shedding in the Nervous System by chemical signaling. We hope this broad spectrum of topics covered in this thematic issue can be considered a useful tool for colleagues, students, physicians, and in general terms professionals of health sciences around the world as a guide to get introduced in all thesefascinating themes.