Ageing-related decline in adenosine A1 receptor binding in the rat brain: an autoradiographic study.
The adenosine system has important neuromodulatory and neuroprotective functions in the brain. Several lines of evidence suggest that ageing is associated with major alterations in the adenosine system, which may be partially responsible for changes in sleep, mood, and cognition. In the present study, we examined adenosine A1 receptor density in the rat brain by means of quantitative autoradiography to obtain a detailed anatomical overview of the changes during ageing. A1 receptor binding was assessed in young, old, and senescent animals of 3, 24, and 30 months old, respectively. There was a clear age-dependent reduction in adenosine A1 receptors in most of the brain areas examined, but the magnitude of this reduction varied greatly among regions. Also, whereas some regions displayed a gradual decline in A1 binding sites across the three age classes, other regions showed a particularly strong decrease between the ages of 24 and 30 months. For example, whereas the hippocampus and thalamus showed a gradual decline in A1 binding, some cortical and septal regions showed a more abrupt decline after the age of 24 months. Since particularly in rats many studies have used animals at the age of 24 months or even less, the ageing-related decline in adenosine A1 signaling might have been underestimated.
Department of Molecular Neurobiology, Graduate School of Behavioral and Cognitive Neurosciences, University of Groningen, Groningen, The Netherlands. p.meerlo@biol.rug.nl
Peter
P
Meerlo
Viktor
V
Roman
Eszter
E
Farkas
Jan N
JN
Keijser
Csaba
C
Nyakas
Paul G M
PG
Luiten
D000241:Adenosine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D000367:Age Factors; D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D001345:Autoradiography / Q000379:methods*; D001665:Binding Sites; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D043682:Receptor, Adenosine A1 / Q000378:metabolism*; D014018:Tissue Distribution; D014316:Tritium / Q000493:pharmacokinetics
D043682:Receptor, Adenosine A1; D014316:Tritium; C048599:N(6)-cyclopentyladenosine; D000241:Adenosine