Selective changes in the contents of noradrenaline, dopamine and serotonin in rat brain areas during aging.
This study examines the age-associated changes in noradrenaline (NA), dopamine (DA), 3,4-dihydroxyphenyl-acetic acid (DOPAC), serotonin (5-HT) and 5-hydroxy-3-indoleacetic acid (5-HIAA) in different brain areas of rats. DA and DOPAC concentrations in striatum increased at third month of age, remaining without significant variations until 12th month of age, and decreasing in 24-month-old rats. DA concentration dropped in hippocampus, amygdala and brainstem of 24-month-old-rats, whereas DOPAC levels decreased only in hippocampus. These changes suggest an age-dependent deficit of the dopaminergic system, presumably related to a reduced number/activity of DA nigrostriatal and mesolimbic neurons. An age-induced decline in NA content was found in the pons-medulla, the area containing NA neuronal bodies. Concentrations of 5-HT were reduced with aging in frontal cortex, showing a tendency to decrease in all brain areas examined. The increased 5-HIAA/5-HT ratio found in frontal cortex, amygdala and striatum suggests an age-related decreased synthesis and an accelerated 5-HT metabolism. The 5-HIAA content decreased in brainstem of the oldest rats. These findings point to a selective impairment of nigrostriatal and mesolimbic DA in aging rats, whereas reductions in NA were restricted to cell bodies region and 5-HT showed changes of different extent in areas of terminals and neuronal cell bodies.
Míguez
J M
JM
Departamento de Biología Funcional y Ciencias de la Salud, Area de Fisiología Animal, Facultad de Ciencias, Universidad de Vigo, Spain. jmmiguez@uvigo.es
Aldegunde
M
M
Paz-Valiñas
L
L
Recio
J
J
Sánchez-Barceló
E
E
D000375:Aging / Q000502:physiology*; D000818:Animals; D015306:Biogenic Monoamines / Q000378:metabolism*; D001921:Brain / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism; D008297:Male; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism; D009435:Synaptic Transmission / Q000502:physiology
D015306:Biogenic Monoamines; D012701:Serotonin; D004298:Dopamine; D009638:Norepinephrine