The modulation of striatal dopamine release correlates with water-maze performance in aged rats.
Cluster analysis of performance during acquisition of a place-learning task in the water maze distinguished between subpopulations of aged rats (25-27 months) classified as moderately (AMI) or severely impaired (ASI) in comparison with young adults (3-5 months). Using a slice-superfusion device, electrically or nicotine-evoked release of dopamine from striatum was assessed in the presence of GR-55,562 (5-HT(1B) receptor antagonist), methiotepin (mixed 5-HT(1/2) receptor antagonist) and/or sulpiride (D(2)/D(3) receptor antagonist). The main neuropharmacological results demonstrated age-related alterations in the 5-HT(1B)- and D(2)/D(3)-mediated modulation of electrically evoked striatal dopamine release. Regression analyses indicated a possible contribution of such alterations to the age-related behavioural deficits: the larger the deficit, the weaker the electrically evoked release under 5-HT(1B) and D(2)/D(3) receptor blockade. Extending our recent report on the modulation of striatal acetylcholine release in aged rats [Cassel et al., 2007. Neurobiol. Aging 28, 1270-1285], these new findings make dopaminergic and serotonergic functional alterations potential candidates to participate in age-related deficits in the water maze, most probably in interaction with formerly described cholinergic dysfunctions.
Rutz
Susanne
S
Institut für Experimentelle und Klinische Pharmakologie und Toxikologie der Universität Freiburg, Neuropharmakologisches Labor, Hansastrasse 9A, D-79104 Freiburg, Germany.
Majchrzak
Monique
M
Siedschlag
Veronika
V
Barbelivien
Alexandra
A
Harati
Hayat
H
Rothmaier
Anna Katharina
AK
Feuerstein
Thomas J
TJ
Jackisch
Rolf
R
Cassel
Jean-Christophe
JC
D000222:Adaptation, Physiological / Q000502:physiology; D000375:Aging / Q000502:physiology*; D000818:Animals; D003342:Corpus Striatum / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D005260:Female; D018782:Maze Learning / Q000502:physiology*; D011939:Mental Recall / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans; D011985:Receptors, Serotonin / Q000378:metabolism*; D013647:Task Performance and Analysis
D011985:Receptors, Serotonin; D004298:Dopamine