title: Co-existence of GABA and Glu transporters in the central nervous system.
abstract: Co-localization of transporters able to recapture the released or endogenously synthesized transmitter (homotransporters) and of transporters that can selectively take up transmitters/modulators originating from neighbouring structures (heterotransporters) has been demonstrated to occur within the same axon terminal of several neuronal phenotypes. Activation of terminal heterotransporters invariably leads to the release of the transmitter specific to the terminal. Heterotransporters are also increasingly reported to exist on neuronal soma/dendrites and nerve terminals, on the basis of morphological experiments. The functions of somatodendritic heterotransporters has been investigated only in a very limited number of cases. Release-regulating GABA heterotransporters of the GAT-1 type exist on Glu nerve terminals in different rodent brain regions including spinal cord. Activation of GABA heterotransporters provokes release of Glu, which takes place by reversal of the Glu homotransporter and by anion channel opening. Interestingly, the release of Glu induced by GABA in spinal cord is dramatically enhanced in a transgenic mouse model of amyotrophic lateral sclerosis and this effect seems to represent the most precocious mechanism that increases extracellular Glu concentration, reported to occur in the pathomechanism.
authors.affiliation: Department of Experimental Medicine, Pharmacology and Toxicology Section, Genoa, Italy. bonanno@pharmatox.unige.it
authors.forename: Giambattista
authors.initials: G
authors.lastname: Bonanno
authors.forename: Luca
authors.initials: L
authors.lastname: Raiteri
authors.forename: Silvio
authors.initials: S
authors.lastname: Paluzzi
authors.forename: Simona
authors.initials: S
authors.lastname: Zappettini
authors.forename: Cesare
authors.initials: C
authors.lastname: Usai
authors.forename: Maurizio
authors.initials: M
authors.lastname: Raiteri
mesh_terms: D027322:Amino Acid Transport System X-AG / Q000378:metabolism*; D000818:Animals; D002490:Central Nervous System / Q000378:metabolism*; D050485:GABA Plasma Membrane Transport Proteins / Q000378:metabolism*; D006801:Humans; D018377:Neurotransmitter Agents / Q000378:metabolism; D013574:Synaptosomes / Q000378:metabolism
chemical_list: D027322:Amino Acid Transport System X-AG; D050485:GABA Plasma Membrane Transport Proteins; D018377:Neurotransmitter Agents