A role for Cav1.3 in rat intestinal calcium absorption

被引：57

作者：

Morgan, EL ^{[1
]}

Mace, OJ ^{[1
]}

Helliwell, PA ^{[1
]}

Affleck, J ^{[1
]}

Kellett, GL ^{[1
]}

机构：

[1] Univ York, Dept Biol, Area 3, York YO10 5YW, N Yorkshire, England

来源：

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS | 2003年 / 312卷 / 02期

关键词：

calcium; Ca(v)1.3 alpha(1); neuroendocrine; L-type channel; transport; intestine;

D O I：

10.1016/j.bbrc.2003.10.138

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 [生物化学与分子生物学]; 081704 [应用化学];

摘要：

Active Ca2+ absorption through epithelial Ca2+ channels TRPV5/6 in duodenum is activated by hyperpolarisation. However, when diet and Ca2+ are plentiful, digestion products cause depolarisation. We therefore used homology-based PCR from a rat jejunal mucosal cDNA preparation to reveal the presence of the neuroendocrine L-type isoform Ca(v)1.3alpha(1). Immunocytochemical labelling and immunoblotting localised Ca(v)1.3alpha(1) protein in apical membrane from proximal jejunum to mid ileum. Perfusion studies in vivo with 1.25 mM luminal Ca2+ revealed L-type channel activity. Inhibition of glucose absorption with phloridzin strongly inhibited Ca-45(2+) absorption; absorption was inhibited by nifedipine and Mg2+ and activated by Bay K 8644, none of which affect TRPV5/6. At 10 mM Ca2+, nifedipine inhibited Ca-45(2+) absorption with a time course similar to that at 1.25 mM Ca2+: absorption was therefore channel-mediated rather than paracellular. We suggest that in times of dietary sufficiency, Ca(v)1.3 may mediate a significant route of Ca2+ absorption into the body. (C) 2003 Elsevier Inc. All rights reserved.

引用

页码：487 / 493

页数：7

共 31 条

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