Distribution of the Na+/Ca2+ exchange protein in developing rabbit myocytes.
The Na+/Ca2+ exchanger is a major pathway for transmembrane flux of Ca2+ in cardiac cells. Immunolabeling in adult rabbit myocytes showed localization of the Na+/Ca2+ exchanger to the peripheral sarcolemma and especially in the T tubules. Previous studies have also demonstrated higher Na+/Ca2+ exchanger activity in fetal and newborn rabbit hearts in which the T tubular system is not completely developed. Indirect immunofluorescent studies were performed to localize the Na+/Ca2+ exchanger in isolated myocytes from immature (5, 11, 17, and 30 days) and adult rabbits. Cells were incubated with a monoclonal antibody to the exchanger followed by fluorescein-labeled goat anti-mouse antibody. It is found that at 5 days of age the immunofluorescent labeling was very intense and confined to the peripheral sarcolemma. After 11 days of age, localization of labeling followed the development of the T tubules. The exchanger appeared in the T tubules as soon as they were formed. The Na+/Ca2+ exchange protein is abundantly localized to the peripheral sarcolemma before and during the development of T tubule system.
Chen
F
F
University of California, Los Angeles School of Medicine 90024-1760, USA.
Mottino
G
G
Klitzner
T S
TS
Philipson
K D
KD
Frank
J S
JS
D000375:Aging / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D002352:Carrier Proteins / Q000378:metabolism*; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives; D005455:Fluorescent Antibody Technique; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D011817:Rabbits; D019831:Sodium-Calcium Exchanger; D014018:Tissue Distribution; D014909:Wheat Germ Agglutinins
D002352:Carrier Proteins; D019831:Sodium-Calcium Exchanger; D014909:Wheat Germ Agglutinins; C047939:fluorescein isothiocyanate-wheat germ agglutinin; D016650:Fluorescein-5-isothiocyanate