Aging does not alter cytosolic calcium levels of cortical synaptosomes in Fischer 344 rats.
Several lines of experimental evidence support an association between altered Ca2+ regulation and aging. It has been supposed that free cytosolic Ca2+ concentrations ([Ca2+]i) may decrease or increase in aged animals. In this study, both resting and KCl-stimulated [Ca2+]i were measured in purified cortical synaptosomes from young (3 mo.), middle-aged (12 mo.), and old (24 mo.) Fischer 344 rats. Two additional groups of rats were included, one middle-aged and one old which were trained on a treadmill for 6 months prior to experimentation. The [Ca2+]i was determined using the fluorescent Ca2+ chelator fura-2. Net KCl-dependent changes (delta K) in [Ca2+]i were determined by the difference between stimulatory (100 microM Ca2+/60 mM KCl) and resting (100 microM Ca2+/5 mM KCl buffer) conditions among the 3 age groups. Significant increases in [Ca2+]i were observed in each age group upon depolarization with 60 mM KCl. However, there were no significant age-dependent differences in either resting [Ca2+]i or KCl-stimulated [Ca2+]i.
Department of Kinesiology and Health Education, University of Texas, Austin 78712.
R P
RP
Farrar
S M
SM
Rezazadeh
J L
JL
Morris
J E
JE
Dildy
K
K
Gnau
S W
SW
Leslie
D000375:Aging / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002540:Cerebral Cortex / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology; D003600:Cytosol / Q000378:metabolism; D008297:Male; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011916:Rats, Inbred F344; D013574:Synaptosomes / Q000378:metabolism
D011188:Potassium; D002118:Calcium