title: In vivo amino acid release from the striatum of aging rats: adenosine modulation.
abstract: The release of glutamate, aspartate, GABA, and taurine from the striatum of young (3 months), mature (12 months), and old (22 months), freely moving male rats was investigated by using a microdialysis fiber inserted transversally in the striatum. In old rats basal extracellular glutamate and aspartate levels were decreased vs. young rats (-38 and -49%, respectively). GABA and taurine levels were unmodified by age. In the presence of the adenosine receptor antagonist 8-phenyltheophilline (8-pT) at the concentration of 50 microM, both K(+)-evoked releases of glutamate and aspartate were more than doubled in young, but not in mature and old rats. 8-pT at the concentration of 500 microM significantly decreased glutamate basal levels and K(+)-evoked aspartate release in old rats only. GABA and taurine releases were not affected by 8-pT at either dose. Our findings indicate a modified adenosine modulation on glutamate and aspartate release in aged rats, that could result from a change in the balance between A1 and A2a adenosine receptor density or an alteration of A1 and A2a receptor-effector coupling.
authors.affiliation: Department of Preclinical and Clinical Pharmacology, University of Florence, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Corsi
authors.forename: M
authors.initials: M
authors.lastname: Pazzagli
authors.forename: L
authors.initials: L
authors.lastname: Bianchi
authors.forename: L
authors.initials: L
authors.lastname: Della Corte
authors.forename: G
authors.initials: G
authors.lastname: Pepeu
authors.forename: F
authors.initials: F
authors.lastname: Pedata
mesh_terms: D000241:Adenosine / Q000502:physiology*; D000375:Aging / Q000378:metabolism*; D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D018846:Excitatory Amino Acids / Q000378:metabolism; D008297:Male; D017551:Microdialysis; D017072:Neostriatum / Q000254:growth & development / Q000378:metabolism*; D058915:Purinergic P1 Receptor Antagonists; D051381:Rats; D017208:Rats, Wistar; D013654:Taurine / Q000378:metabolism; D013806:Theophylline / Q000031:analogs & derivatives / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D000596:Amino Acids; D018846:Excitatory Amino Acids; D058915:Purinergic P1 Receptor Antagonists; D013654:Taurine; D005680:gamma-Aminobutyric Acid; D013806:Theophylline; C028322:8-phenyltheophylline; D000241:Adenosine