Inhibitory effects of purified antibody against α-1 repeat(117-137)on Na+-Ca2+exchange and L-type Ca2+currents in rat cardiomyocytes
- Author:
- No author available
- Journal Title:
- ACTA PHYSIOLOGICA SINICA
- Issue:
- 5
- DOI:
- No doi available
- Key Word:
- 钠-钙交换体;膜片钳技术;心肌细胞;抗体;sodium-calcium exchanger;patch-clamp technique;cardiac myocytes;antibody
Abstract： Considering that α-1 repeat region may be involved in the ion binding and translocation of Na+-Ca2+exchanger(NCX),it is possible that the antibodies against NCX a-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+-Ca2+exchange current(INa/Ca)in adult rat cardiomyocytes.To evaluate the functional specificity of this antibody,its effects on L-type Ca2+current(ICa,L),voltage-gated Na+current(INa)and delayed rectifier K+current(IK)were also observed.The amino acid sequences ofα-1(117-137)in NCX and residues 1 076-1 096 within L-type Ca2+channel were compared using EMBOSS Pairwise Alignment Algorithms.The results showed that outward and inward INa/Ca were decreased by the antibody against α-1(117-137)dose-dependently in the concentration range from 10 to 160 nmol/L,with IC50 values of 18.9 nmol/L and 22.4 nmol/L,respectively.Meanwhile,the antibody also decreased ICa.L.in a concentration-dependent manner with IC50 of 22.7 nmol/L.No obvious effects of the antibody on INa and IK were observed.Moreover,comparison of the amino acid sequences showed there was 23.8% sequence similarity between NCXα-1(117-137)and residues 1 076-1 096 within L-type Ca2+channel.These results suggest that antibody against α-1(117-137)is a blocking antibody to NCX and can also decrease ICa,L in a concentration-dependent manner,while it does not have obvious effects on INa and IK.
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