Intracerebral microdialysis was used to measure basal levels and potassium (K+)-stimulated overflow of dopamine (DA), homovanillic acid (HVA) and dihydroxyphenylacetic acid (DOPAC), in the dorsal striatum of young (6 months) and aged (24 months) Fischer 344 (F344) rats. Basal levels of HVA were lower in aged rats whereas basal DA and DOPAC did not differ significantly between the two groups. The administration of three low to moderate doses of K+ (10, 25, and 50 mM) through the microdialysis probe for one collection period revealed differences between the two age groups of F344 rats. DA overflow increased in a dose-dependent manner in the young but not aged rats. Extracellular levels of DOPAC and HVA decreased during the K+ stimulation and there was a significant difference in the changes in HVA produced by K+ stimulation in the young vs aged animals. These data support the hypothesis that low to moderate doses of K+ may be necessary to demonstrate age-related differences in K+-evoked DA overflow, since previous microdialysis studies using higher doses have not reported age-related differences in DA overflow. Copyright (C) 2000 ISDN.
|Number of pages||6|
|Journal||International Journal of Developmental Neuroscience|
|State||Published - Jul 1 2000|
Bibliographical noteFunding Information:
Supported by USPHS grants AG06434 and NS09199.
ASJC Scopus subject areas
- Developmental Neuroscience
- Developmental Biology