TY - JOUR
T1 - The Na+Ca2+ exchanger activity in cerebrocortical nerve endings is reduced in old compared to young and mature rats when it operates as a Ca2+ influx or efflux pathway
AU - Canzoniero, Lorella M T
AU - Rossi, Annamaria
AU - Taglialatela, Maurizio
AU - Amoroso, Salvatore
AU - Annunziato, Lucio
AU - Di Renzo, Gianfranco
PY - 1992/6/11
Y1 - 1992/6/11
N2 - The activity of the Na+Ca2+ exchanger, which regulates the entry and the extrusion of Ca2+ ions from nerve endings was investigated in Percoll-purified cerebrocortical synaptosomes of aged rats. 45Ca2+ uptake in a Na+-free medium and 45Ca2+ efflux in a 145 mM Na+ medium were significantly reduced in cerebrocortical synaptosomes from aged rats (24 months) as compared to those occurring in young (4 months) and mature (14 months) rats. 45Ca2+ influx induced by 55 mM K+, a concentration of K+ ions which selectively promotes Ca2+ entry through voltage-sensitive Ca2+ channels (VSCC), was significantly reduced in mature and aged rats as compared to that occurring in young rats. The impairment of these mechanisms in aged rats is not accompanied by any variation of fura-2 monitored Ca2+ levels under resting and depolarizing conditions.
AB - The activity of the Na+Ca2+ exchanger, which regulates the entry and the extrusion of Ca2+ ions from nerve endings was investigated in Percoll-purified cerebrocortical synaptosomes of aged rats. 45Ca2+ uptake in a Na+-free medium and 45Ca2+ efflux in a 145 mM Na+ medium were significantly reduced in cerebrocortical synaptosomes from aged rats (24 months) as compared to those occurring in young (4 months) and mature (14 months) rats. 45Ca2+ influx induced by 55 mM K+, a concentration of K+ ions which selectively promotes Ca2+ entry through voltage-sensitive Ca2+ channels (VSCC), was significantly reduced in mature and aged rats as compared to that occurring in young rats. The impairment of these mechanisms in aged rats is not accompanied by any variation of fura-2 monitored Ca2+ levels under resting and depolarizing conditions.
KW - Aging
KW - Calcium ion channel
KW - Calcium ion, intracytosolic
KW - Cerebrocortical nerve ending
KW - Intracytosolic calcium ion
KW - Sodium-calcium ion exchanger
KW - Voltage sensitivity
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U2 - 10.1016/0005-2736(92)90344-L
DO - 10.1016/0005-2736(92)90344-L
M3 - Article
C2 - 1616919
AN - SCOPUS:0027117754
VL - 1107
SP - 175
EP - 178
JO - Biochimica et Biophysica Acta - Biomembranes
JF - Biochimica et Biophysica Acta - Biomembranes
SN - 0005-2736
IS - 1
ER -