| First Author | Marvão P | Year | 1998 |
| Journal | J Clin Invest | Volume | 102 |
| Issue | 11 | Pages | 1986-93 |
| PubMed ID | 9835624 | Mgi Jnum | J:51326 |
| Mgi Id | MGI:1315103 | Doi | 10.1172/JCI4074 |
| Citation | Marvao P, et al. (1998) Cl- absorption across the thick ascending limb is not altered in cystic fibrosis mice. A role for a pseudo-CFTR Cl- channel. J Clin Invest 102(11):1986-93 |
| abstractText | The cortical thick ascending limb (CTAL) absorbs Cl- via a Na+-K+-Cl- cotransport at the apical membrane and several Cl- channels at the basolateral membrane, including a 9-pS channel having several properties of the cystic fibrosis transmembrane conductance regulator (CFTR). Having checked that CFTR mRNA is present in the mouse CTAL, we investigated whether this channel is a CFTR molecule by applying the patch-clamp technique to CTALs microdissected from CFTR knockout mice (cftrm1Unc). The 9-pS channel was active in cell-attached patches from tubules of mice homozygous for the disrupted cftr gene [CFTR (-/-)] at the same frequency and with the same activity (NPo) as in normal [CFTR (+/+)] or heterozygous [CFTR (+/-)] mice. The conductive properties of the channel, studied on inside-out patches, were identical in CFTR (-/-), CFTR (+/+), and CFTR (+/-) tubules, as were the sensitivities to internal pH and internal ATP, two typical features of this channel. In addition, the Cl- absorption in isolated, microperfused CTALs and the Na+-K+-Cl- cotransport activity were identical in CFTR (-/-), CFTR (+/+), and CFTR (+/-) mice. These results show that the 9-pS Cl- channel is distinct from CFTR, and that the CFTR protein has no influence on the Cl- absorption in this part of the renal tubule. |
