TROPHIC ACTIONS OF EXTRACELLULAR NUCLEOTIDES AND NUCLEOSIDES ON GLIALAND NEURONAL CELLS

In addition to their well-established roles as neurotransmitters and n euromodulators, growing evidence suggests that nucleotides and nucleos ides might also act as trophic factors in both the central and periphe ral nervous systems, Specific extracellular receptor subtypes for thes e compounds are expressed on neurons, glial and endothelial cells, whe re they mediate strikingly different effects,These range from inductio n of cell differentiation and apoptosis, mitogenesis and morphogenetic changes, to stimulation of synthesis or release, or both, of cytokine s and neurotrophic factors, both under physiological and pathological conditions, Nucleotides and nucleosides might be involved in the regul ation of development and plasticity of the nervous system, and in the pathophysiology of neurodegenerative disorders, Receptors for nucleoti des and nucleosides could represent a novel target for the development of therapeutic strategies to treat incurable diseases of the nervous system, including trauma- and ischemia-associated neurodegeneration, d emyelinating and aging-associated cognitive disorders.