ISSN:
1432-2013
Keywords:
Isolated thick ascending limb
;
Microperfusion
;
Divalent cation and potassium transport
;
Microprobe analysis
;
Transepithelial voltage
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Isolated segments of rat cortical (cTAL) and medullary (mTAL) thick ascending limbs were microperfused and the transepithelial net fluxes (Jx) were determined by measuring the composition of the collected fluid with an electron microprobe. When perfused with symmetrical solutions both segments showed similar JNa and jCl and lumen-positive transepithelial voltage (V te=7–8 mV). JMg, JCa and JK were not significantly different from zero. When perfused with asymmetrical solutions (lumen 50 mM, bath 150 mM NaCl), the mean Vte were 23 mV and 17 mV in the cTAL and mTAL respectively; this rise was accompanied by significant increases in JMg and JCa in the cTAL, but not in the mTAL, and a marked increase in JK in both segments. It is concluded that, in the rat, divalent cations can be reabsorbed in the cTAL, and K+ can be reabsorbed in the cTAL and mTAL. The transport is voltage-dependent. The mTAL can reabsorb neither Mg2+ nor Ca2+, whatever Vte.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00374924
