Age-related changes in potassium-evoked overflow of dopamine in the striatum of the rhesus monkey.
Rapid (5 Hz) chronoamperometric recordings using Nafion-coated carbon fiber electrodes (30-90 microns o.d.) combined with pressure-ejection of potassium from micropipettes were used to investigate potassium-evoked overflow of dopamine (DA) in the striatum of young (5 to 10 years old) and middle-aged (19 to 23 years old) anesthetized rhesus monkeys. The potassium-evoked DA-like signals from the 19- to 23-year-old animals were significantly lower in amplitude than those recorded in the young animals. In addition, the temporal dynamics of DA signals in the caudate nucleus of middle-aged animals were faster, while the time courses of the signals recorded in the putamen of middle-aged monkeys were significantly longer as compared to the signals recorded from young animals. Moreover, home cage activity levels of the middle-aged animals were significantly lower. Taken together, these data support age-related changes in the output of DA from DA fibers in the striatum of middle-aged monkeys.
Gerhardt
G A
GA
Department of Psychiatry, University of Colorado Health Sciences Center, Denver 80262, USA.
Cass
W A
WA
Henson
M
M
Zhang
Z
Z
Ovadia
A
A
Hoffer
B J
BJ
Gash
D M
DM
D000367:Age Factors; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D002421:Caudate Nucleus / Q000187:drug effects / Q000502:physiology; D003342:Corpus Striatum / Q000502:physiology*; D004298:Dopamine / Q000502:physiology*; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology*; D005260:Female; D008253:Macaca mulatta; D011188:Potassium / Q000494:pharmacology*; D011699:Putamen / Q000187:drug effects / Q000502:physiology
D011188:Potassium; D004298:Dopamine