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Juvenile Murine Distal Colon Exhibits Increased CFTR, ENAC and Basolateral Transport
Author(s) -
Gawenis Lara,
Gawenis James
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.lb653
Subject(s) - amiloride , endocrinology , chemistry , ion transporter , epithelial sodium channel , crypt , juvenile , medicine , sodium–hydrogen antiporter , epithelial polarity , bumetanide , apical membrane , biology , sodium , biochemistry , cell , genetics , organic chemistry , membrane
Previous studies suggest increased epithelial ion transport in neonatal colon. We hypothesized that apical and basolateral transport activities are increased in distal colon of juvenile mice and that this tissue is a model for studying transport during intestinal maturation. Short‐circuit current (I sc ) responses to cAMP and inhibitors were measured in distal colon from adult (2–4 months) and juvenile (14–16 days) wild‐type mice. In physiologic Ringers (Cl − and HCO 3 − containing), the I sc response to amiloride and the peak cAMP‐induced increase in I sc were significantly greater in juvenile as compared to adult tissues. The increase in peak I sc was abolished by inhibition of carbonic anhydrases or EIPA (to inhibit coupled NHE1 Na + /H + exchanger/AE2 Cl − /HCO 3 − exchanger). Removal of HCO 3 − from the perfusion Ringers (Cl − ‐only) also abolished the difference between juvenile and adult distal colon; however, the ÄI sc response to cAMP was increased or unchanged due to increased NKCC1 activity. Together these findings support the hypothesis that apical channel activity facilitated by the basolateral NHE1/AE2/CA transport metabolon enhances Cl − secretion in juvenile distal colon. Current studies are focused on evaluating the altered activity to determine if these changes reflect changes in expression or intestinal morphology in the post‐weaning period (as the intestine matures). Supported by AGA‐FDHN and CFFT.