In vivo assessment of striatal dopamine release in the aged male Fischer 344 rat.
A microdialysis probe was implanted into the striatum of young (4- to 5-month-old) and aged (26- to 27-month-old) Fischer 344 male rats to assess age-related alterations in striatal dopamine (DA) release. Basal levels of DA and the magnitude of DA response evoked by 50 mM and 100 mM high potassium (K+) in aged rats were similar to those in young rats. Furthermore, K(+)-evoked DA release did not correlate with motor performance within either age group. In contrast, amphetamine (250 microM) evoked-DA release of aged rats was significantly lower than that of young rats. Moreover, the enhancement of K(+)-evoked DA release by oxotremorine (500 microM) was significantly attenuated in aged rats. These results indicate that a putative DA release mechanism and its cholinergic modulation of the aged striatum are impaired.
Kametani
H
H
Molecular Physiology and Genetics Section, Nathan W. Shock Laboratories, Gerontology Research Center, National Institute on Aging, Baltimore, MD 21224, USA.
Iijima
S
S
Spangler
E L
EL
Ingram
D K
DK
Joseph
J A
JA
D000375:Aging / Q000378:metabolism*; D000661:Amphetamine / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D017660:Autoreceptors / Q000378:metabolism; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D015259:Dopamine Agents / Q000494:pharmacology; D008297:Male; D017551:Microdialysis; D009043:Motor Activity / Q000187:drug effects; D018721:Muscarinic Agonists / Q000494:pharmacology; D010095:Oxotremorine / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011916:Rats, Inbred F344; D011954:Receptors, Dopamine / Q000378:metabolism
D017660:Autoreceptors; D015259:Dopamine Agents; D018721:Muscarinic Agonists; D011954:Receptors, Dopamine; D010095:Oxotremorine; D000661:Amphetamine; D011188:Potassium; D004298:Dopamine