Age-related alteration of the adenosine/dopamine balance in the rat striatum.
An antagonistic interaction between adenosine A2A- and dopamine D2-receptors has been described. Radioligand binding experiments showed a predominant reduction in the number of D2 vs. A2A-receptors in the striatum of aged compared to young rats. The A2A-receptor-mediated antagonistic modulation of D2-receptor binding remained unchanged in aged animals. In striatal homogenates a significant increase in adenosine and no change in dopamine content was found in aged vs. young rats. These results reveal the existence of an age-dependent imbalance of adenosine vs. dopamine in favor of adenosine, which involves both presynaptic and postsynaptic mechanisms.
Popoli
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P
Department of Pharmacology, Istituto Superiore de Sanità, 00161 Roma, Italy.
Betto
P
P
Rimondini
R
R
Reggio
R
R
Pézzola
A
A
Ricciarello
G
G
Fuxe
K
K
Ferré
S
S
D000241:Adenosine / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D000375:Aging / Q000378:metabolism*; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001667:Binding, Competitive / Q000502:physiology; D003342:Corpus Striatum / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D018492:Dopamine Antagonists / Q000494:pharmacology; D008297:Male; D010627:Phenethylamines / Q000494:pharmacology; D020891:Raclopride; D051381:Rats; D017208:Rats, Wistar; D018341:Receptors, Adrenergic, alpha-2 / Q000032:analysis; D017448:Receptors, Dopamine D2 / Q000032:analysis; D012457:Salicylamides / Q000494:pharmacology; D014316:Tritium
D000959:Antihypertensive Agents; D018492:Dopamine Antagonists; D010627:Phenethylamines; D018341:Receptors, Adrenergic, alpha-2; D017448:Receptors, Dopamine D2; D012457:Salicylamides; D014316:Tritium; C061282:2-(4-(2-carboxyethyl)phenethylamino)-5'-N-ethylcarboxamidoadenosine; D020891:Raclopride; D000241:Adenosine; D004298:Dopamine