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.
Molecular Physiology and Genetics Section, Nathan W. Shock Laboratories, Gerontology Research Center, National Institute on Aging, Baltimore, MD 21224, USA.
H
H
Kametani
S
S
Iijima
E L
EL
Spangler
D K
DK
Ingram
J A
JA
Joseph
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