Aging does not affect steady-state expression of the Na+/Ca2+ exchanger in rat brain.
1. Steady-state protein and mRNA levels of the Na+/Ca2+ exchanger were studied in old (24-month) and young (3-month) brains of male Fischer 344 rats by Western and Northern analysis. 2. Northern analysis with a cDNA proble for the Na+/Ca2+ exchanger amplified from human brain RNA indicated the presence of two transcripts for the Na+/Ca2+ exchanger (6 and 16 kb). Both transcripts were present in similar abundance in the cerebrum and hippocampus. In the cerebellum the 6-kb transcript predominated. The cerebellum had the highest overall level of expression. There were no significant age-related effects seen on the level of expression of either transcript in each of the brain areas tested. 3. Western analysis of plasma membrane vesicles purified from cerebral cortex identified a single protein of 116 kDa. Consistent with the Northern analysis, no age-related effect on protein levels was seen. 4. The mechanisms underlying altered Na+/Ca2+ exchange activity in aging rat brain (Michaelis, 1989) most likely do not involve changes in gene expression and are therefore more likely to represent posttranslation modifications of the protein.
Colvin
R A
RA
Department of Biological Sciences, Ohio University, Athens 45701, USA. colvin@ouvaxa.cats.ohiou.edu
Walker
J P
JP
Schummers
J
J
Davis
N
N
D000375:Aging / Q000378:metabolism*; D000704:Analysis of Variance; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D001921:Brain / Q000254:growth & development / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002352:Carrier Proteins / Q000032:analysis / Q000096:biosynthesis*; D002531:Cerebellum / Q000378:metabolism; D017931:DNA Primers; D015342:DNA Probes; D018507:Gene Expression Regulation, Developmental; D006624:Hippocampus / Q000378:metabolism; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D051381:Rats; D011916:Rats, Inbred F344; D012964:Sodium / Q000378:metabolism; D019831:Sodium-Calcium Exchanger; D014158:Transcription, Genetic
D002352:Carrier Proteins; D017931:DNA Primers; D015342:DNA Probes; D012333:RNA, Messenger; D019831:Sodium-Calcium Exchanger; D012964:Sodium; D002118:Calcium