Stimulation of Na+-Ca2+ exchange by purified antibody against alpha-2 repeat of Na+-Ca2+ exchanger in rat cardiomyocytes.
OBJECTIVE
The aim of the present study was to investigate the effect of the antibody against alpha-2 repeat on Na+-Ca2+ exchanger (NCX) current (I(Na/Ca)). To evaluate the functional specificity of this antibody, its effects on L-type Ca2+ current (I(Ca,L)), voltage-gated Na+ current (I(Na)) and delayed rectifier K+ current (I(K)) were also observed.


METHODS
The whole-cell patch-clamp technique was used in this study.


RESULTS
The antibody against alpha-2 repeat augmented both the outward and inward Na+-Ca2+ exchanger current concentration-dependently, with EC(50) values of 27.9 nmol/L and 24.7 nmol/L, respectively. Meanwhile, the antibody could also increase I(Ca,L) in a concentration-dependent manner with the EC(50) of 33.6 nmol/L. Effects of the antibody on I(Na) and I(K) were not observed in the present study.


CONCLUSIONS
The present results suggest that antibody against alpha-2 repeat is a stimulating antibody to NCX and could also increase I(Ca,L) in a concentration-dependent manner, but did not have an obvious effect on I(Na) and I(K).
Feng
Qi-long
QL
Department of Physiology, Shanxi Medical University, Taiyuan 030001, China.
Wu
Dong-mei
DM
Cui
Xiang-li
XL
Zhao
Hua-chen
HC
Fan
Guo-quan
GQ
Zhao
Lu-ying
LY
Wu
Bo-wei
BW
D000595:Amino Acid Sequence; D000818:Animals; D019138:Antibodies, Blocking / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D004594:Electrophysiology; D008969:Molecular Sequence Data; D032383:Myocytes, Cardiac / Q000187:drug effects*; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D012964:Sodium / Q000378:metabolism*; D019831:Sodium-Calcium Exchanger / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*
D019138:Antibodies, Blocking; D019831:Sodium-Calcium Exchanger; D012964:Sodium; D002118:Calcium