Cyclic nucleotide-gated cation channels mediate sodium and calcium influx in rat colon

W. Qiu, B. Lee, M. Lancaster, W. Xu, S. Leung, S. E. Guggino

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


We found mRNA for the three isoforms of the cyclic nucleotide-gated nonselective cation channel expressed in the mucosal layer of the rat intestine from the duodenum to the colon and in intestinal epithelial cell lines in culture. Because these channels are permeable to sodium and calcium and are stimulated by cGMP or cAMP, we measured 8-bromo-cGMP-stimulated sodium-mediated short-circuit current (I(sc)) in proximal and distal colon and unidirectional 45Ca2+ fluxes in proximal colon to determine whether these channels could mediate transepithelial sodium and calcium absorption across the colon. Sodium-mediated I(sc), stimulated by 8-bromo-cGMP, were inhibited by dichlorobenzamil and l-cis-diltiazem, blockers of cyclic nucleotide-gated cation channels, suggesting that these ion channels can mediate transepithelial sodium absorption. Sodium-mediated I(sc) and net transepithelial 45Ca2+ absorption were stimulated by heat-stable toxin from Escherichia coli that increases cGMP. Addition of l-cis-diltiazem inhibited the enhanced transepithelial absorption of both ions. These results suggest that cyclic nucleotide-gated cation channels simultaneously increase net sodium and calcium absorption in the colon of the rat.

Original languageEnglish
Pages (from-to)C336-C343
JournalAmerican Journal of Physiology - Cell Physiology
Issue number2 47-2
StatePublished - 2000


  • Calcium absorption
  • Cation channels
  • Sodium absorption

ASJC Scopus subject areas

  • Physiology
  • Cell Biology


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