Synucleins expression in the nervous system of non-mammalian Vertebrates. Federica De Angelis*2, Arianna Casini1, Carla Cioni2, Loredana D’Este1, Mattia Toni2, Rosa Vaccaro1, GiorgioVivacqua1, ShunYu3. 1 Department of Anatomical, Histological, Forensic Medicine and Orthopedics Sciences, Sapienza University, Rome, Italy 2 Department of Biology and Biotechnology “Charles Darwin”, Sapienza University, Rome, Italy 3 Department of Neurobiology, Beijing Institute of Geriatrics, Xuamwu Hospital, China Capital Medical University, Beijing, China * Speaker at Ponzano meeting ABSTRACT Alpha Synuclein (α-syn) is a 140 amino acid protein, highly expressed in the central nervous system of different vertebrates and abnormally accumulated in Parkinson’s disease and other degenerative disorders, known as synucleinopathies. Although most physiological functions of αsyn remain elusive, this protein possesses chaperone properties and it is involved in vesicular storage and docking, neurotransmitters release and synaptic plasticity. Although non-mammalian synucleins have been relatively well characterized, present knowledge about their cellular localization is still scarce. Aim of the study is to analyze the expression and localization of synucleins in the central nervous system of representative specimens of the principal taxa of non mammalian vertebrate in order to add new perspectives to physiological roles of synucleins during evolution and neurological disorders. On the base of comparative analysis of the available synuclein sequences, Cyprinus carpio, Xenopus laevis and Anolis carolinensis have been chosen as animal models. We have described the distribution of α-syn immuno-reactivity in the carp brain and spinal cord. Present results show that α-syn immuno-reactivity is mainly distributed in motor and reticular pathways, throughout the brainstem and the spinal cord. Moreover, α-syn is also localized into small beaded fibers innervating the main forebrain regions including basal telencephalon, preoptic region and hypothalamus. In motor and reticular nuclei α-syn is clearly co-distributed with ChAT. Therefore, the putative α-syn positive neurons may represent a subpopulation of cholinergic neurons.