title: [(11)C]-DASB microPET imaging in the aged rat: frontal and meso-thalamic increases in serotonin transporter binding.
abstract: Whereas molecular imaging studies in the aging human brain have predominantly demonstrated reductions in serotonin transporter (5-HTT) availability, the majority of the rodent studies, using autoradiographic methods, report increases in neural 5-HTT levels with age. To our knowledge, however, no previous rodent studies have assessed this topic in vivo, and therefore it remains unclear whether this discrepancy arises from methodological or inter-species differences. We performed an [(11)C]-DASB microPET study to evaluate the effects of aging on 5-HTT availability in the rat brain. To generate binding potential estimates, quantitative tracer kinetic modeling was applied using the simplified reference tissue model. A global increase in whole-brain [(11)C]-DASB binding potential was observed in the aged rats in comparison to the control group. More specifically, regional analyses revealed a highly significant increase in 5-HTT binding in the medial frontal cortex, and more modest increments in the midbrain/thalamus. Our results suggest that the frontal cortex represents a site of robust age-related alterations in the rat serotonergic system, and stress the need for further research assessing this topic in the human frontal cortex. Moreover, these findings suggest that the reported discrepancies between rodent and human data may reflect a divergence in the aging processes affecting human and rat serotonergic terminals.
authors: Departament de Psiquiatria i Medicina Legal, Universitat Autònoma de Barcelona, Bellaterra, Spain.
authors: Elseline
authors: E
authors: Hoekzema
authors: Santiago
authors: S
authors: Rojas
authors: Raúl
authors: R
authors: Herance
authors: Deborah
authors: D
authors: Pareto
authors: Sergio
authors: S
authors: Abad
authors: Xavier
authors: X
authors: Jiménez
authors: Francisca P
authors: FP
authors: Figueiras
authors: Foteini
authors: F
authors: Popota
authors: Alba
authors: A
authors: Ruiz
authors: Núria
authors: N
authors: Flotats
authors: Francisco J
authors: FJ
authors: Fernández
authors: Milagros
authors: M
authors: Rocha
authors: Mariana
authors: M
authors: Rovira
authors: Víctor M
authors: VM
authors: Víctor
authors: Juan D
authors: JD
authors: Gispert
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D001596:Benzylamines / Q000378:metabolism; D002250:Carbon Radioisotopes / Q000378:metabolism; D005625:Frontal Lobe / Q000000981:diagnostic imaging / Q000378:metabolism*; D008297:Male; D026901:Membrane Transport Proteins / Q000378:metabolism*; D049268:Positron-Emission Tomography / Q000379:methods; D051381:Rats; D050486:Serotonin Plasma Membrane Transport Proteins / Q000378:metabolism*; D013788:Thalamus / Q000000981:diagnostic imaging / Q000378:metabolism*
chemical_list: D001596:Benzylamines; D002250:Carbon Radioisotopes; D026901:Membrane Transport Proteins; C420885:N,N-dimethyl-2-(2-amino-4-cyanophenylthio)benzylamine; D050486:Serotonin Plasma Membrane Transport Proteins