Inhibitory effects of purified antibody against α-1 repeat (117-137) on Na(+)-Ca(2+) exchange and L-type Ca(2+) currents in rat cardiomyocytes.
- Author:
Qi-Long FENG
1
,
2
;
Dong-Mei WU
;
Xiang-Li CUI
;
Hua-Chen ZHAO
;
Yuan-Yuan LIN
;
Lu-Ying ZHAO
;
Bo-Wei WU
Author Information
1. Department of Physiology
2. Department of Pharmacology, Shanxi Medical University, Taiyuan 030001, China.
- Publication Type:Journal Article
- MeSH:
Amino Acid Sequence;
Animals;
Antibodies, Blocking;
metabolism;
pharmacology;
Calcium Channel Blockers;
pharmacology;
Calcium Channels, L-Type;
genetics;
immunology;
metabolism;
Guinea Pigs;
Membrane Potentials;
Molecular Sequence Data;
Myocytes, Cardiac;
drug effects;
metabolism;
physiology;
Patch-Clamp Techniques;
Rats;
Rats, Wistar;
Sodium-Calcium Exchanger;
antagonists & inhibitors;
genetics;
immunology
- From:
Acta Physiologica Sinica
2010;62(5):407-414
- CountryChina
- Language:English
-
Abstract:
Considering that α-1 repeat region may be involved in the ion binding and translocation of Na(+)-Ca(2+) exchanger (NCX), it is possible that the antibodies against NCX α-1 repeat may have a crucial action on NCX activity. The aim of the present study is to investigate the effect of antibody against α-1 repeat (117-137), designated as α-1(117-137), on NCX activity. The antibody against the synthesized α-1(117-137) was prepared and affinity-purified. Whole-cell patch clamp technique was used to study the change of Na(+)-Ca(2+) exchange current (I(Na/Ca)) in adult rat cardiomyocytes. To evaluate the functional specificity of this antibody, its effects on L-type Ca(2+) current (I(Ca,L)), voltage-gated Na(+) current (I(Na)) and delayed rectifier K(+) current (I(K)) were also observed. The amino acid sequences of α-1(117-137) in NCX and residues 1 076-1 096 within L-type Ca(2+) channel were compared using EMBOSS Pairwise Alignment Algorithms. The results showed that outward and inward I(Na/Ca) were decreased by the antibody against α-1(117-137) dose-dependently in the concentration range from 10 to 160 nmol/L, with IC(50) values of 18.9 nmol/L and 22.4 nmol/L, respectively. Meanwhile, the antibody also decreased I(Ca,L) in a concentration-dependent manner with IC(50) of 22.7 nmol/L. No obvious effects of the antibody on I(Na) and I(K) were observed. Moreover, comparison of the amino acid sequences showed there was 23.8% sequence similarity between NCX α-1(117-137) and residues 1 076-1 096 within L-type Ca(2+) channel. These results suggest that antibody against α-1(117-137) is a blocking antibody to NCX and can also decrease I(Ca,L) in a concentration-dependent manner, while it does not have obvious effects on I(Na) and I(K).
