Cytosolic free calcium levels increase with age in rat brain synaptosomes.
Calcium homeostasis in synaptosomes is altered during ageing. The cytosolic free calcium concentration, [Ca2+]i was determined in synaptosomes and crude synaptosomal fractions from 3- and 24-month-old rats with the fluorescent indicator quin-2. The [Ca2+]i were around two times higher in 24-month-old rats than in adults, both under resting conditions and after K depolarization. This difference was still observed after incubation with an endogenous heavy metal chelator. To avoid the calcium buffering effect of quin-2, [Ca2+]i values were determined with the use of a null-point method and with fura-2. These methods confirmed the increase in [Ca2+]i with age in synaptosomes. The increase in [Ca2+]i in nerve endings may be pathologically important in brain ageing.
Martinez
A
A
Departamento de Biologia Molecular, Universidad Autónoma de Madrid, Spain.
Vitórica
J
J
Satrústegui
J
J
D000375:Aging / Q000378:metabolism*; D000818:Animals; D001572:Benzofurans; D001921:Brain / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism* / Q000502:physiology; D003600:Cytosol / Q000378:metabolism; D005456:Fluorescent Dyes; D016257:Fura-2; D008297:Male; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*
D001572:Benzofurans; D005456:Fluorescent Dyes; D011188:Potassium; D002118:Calcium; D016257:Fura-2