Abstract
The possible manifestation of a Cl− -channel defect in intestinal epithelium of CF patients was investigated by Ussing Chamber measurements of the electrical response of stripped ileal mucosa from CF (n=4) and control (N) patients (n=4) undergoing take down of stomas following meconium impaction (CF) or intestinal resection for enterocolitis or atresias (N). Endogenous prostaglandin release was inhibited by serosal (S) and mucosal (M) indomethacin (10−5 M). The short circuit current (SCC) respons (uA/cm2) to glucose (10−2M, M), secretagogues acting through Ca2+ (carbachol 10−4 M, S; histamine 5.10−5M, S; bradyklnin 10−6 M, S,) through cGMP (8-Br-cGMP 10−4M, S), or through cAHP (8-Br-cAMP10−3M, S) is shown below (±S.E.M.).
The negative SCC respons in CF to all secretagogues (except cGMP) was inhibitable by Ba2+ (5.10−3M, M), bumetamide (10−5M, S), DIDS (10−4 H, S) and Cl−-free conditions and presumably reflects the opening of apical K+ and basolateral Cl−-channels by cAMP or Ca2+. It is concluded that: 1.Na+ coupled glucose uptake is unmodified in CF. 2.Apical Cl−-channels in CF enterocytes are either absent or completely insensitive to activating signals (cAMP, cGMP and Ca2+). 3.CF enterocytes contain cAHP and Ca2+ (but not cGMP) sensitive apical K+ channels and basolateral Cl−-channels which are absent or latent in control tissue. 4.The Cl−-channel defect in CF intestine may offer protection against secretory diarrhoea.
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Sinaasappel, M., Bouquet, J., Bot, A. et al. 21 DEFECTIVE REGULATION OF INTESTINAL CHLORIDE CHANNELS IN CYSTIC FIBROSIS (CF). Pediatr Res 24, 408 (1988). https://doi.org/10.1203/00006450-198809000-00044
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DOI: https://doi.org/10.1203/00006450-198809000-00044
