RT info:eu-repo/semantics/article T1 Glycine release in the substantia nigra: Interaction with glutamate and GABA. A1 Morales Pérez, Ingrid A1 García Dopico, José A1 González Hernández, Tomás A1 Gómez García, Isabel A1 Milena Abril, Antonio A1 Obeso Inchausti, José A1 Rodríguez Díaz, Manuel A2 Ciencias Médicas Básicas A2 Grupo de Neurobiología y Neurología Experimental. K1 Glycine K1 Glutamate K1 GABA K1 Zinc K1 Substantia nigra K1 Parkinson’s disease AB Previous studies have reported a high number of glycine (GLY) receptors in the substantia nigra (SN) but a low number of GLY-neurons, suggesting that taurine, a partial agonist of GLY-receptors, is the natural substrate for SN GLY-receptors. By using microdialysis to quantify amino acids in the extracellular space of the SN, we observed an extracellular pool of GLY in the rat that increased after depolarizing with high-Kþ in a Ca2þ-dependent manner and that diffuses through the extracellular space. GLY markedly increased after blocking either the tricarboxylic cycle with fluorocitrate or the glutamine synthetase activity with MSO. Because these products act selectively on glial cells, their effects show glia as a key cell in maintaining the extracellular pool of GLY in the SN. Extracellular GLY was modified by glutamate and glutamate receptor agonists. The local administration of GLY modified the extracellular concentration of GABA. Taken together, the complex regulation of the extracellular level of GLY, its possible glial origin and interaction with glutamate and GABA suggest a volume transmitter role for GLY in the SN, a possibility which also agrees with the recent finding of GLY-transporters in this centre. YR 2006 FD 2006 LK http://riull.ull.es/xmlui/handle/915/38598 UL http://riull.ull.es/xmlui/handle/915/38598 LA en DS Repositorio institucional de la Universidad de La Laguna RD 18-oct-2024