K+ transport in the mesonephric collecting duct system of the toad Bufo bufo : microelectrode recordings from isolated and perfused tubules
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K+ transport in the mesonephric collecting duct system of the toad Bufo bufo : microelectrode recordings from isolated and perfused tubules. / Møbjerg, Nadja; Larsen, Erik Hviid; Novak, Ivana.
In: Journal of Experimental Biology, Vol. 205, No. Pt 7, 2002, p. 897-904.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - K+ transport in the mesonephric collecting duct system of the toad Bufo bufo : microelectrode recordings from isolated and perfused tubules
AU - Møbjerg, Nadja
AU - Larsen, Erik Hviid
AU - Novak, Ivana
N1 - Keywords: Animals; Barium; Bufo bufo; Female; Furosemide; Ion Transport; Kidney Tubules, Collecting; Membrane Potentials; Mesonephros; Microelectrodes; Osmolar Concentration; Ouabain; Potassium; Potassium Channels
PY - 2002
Y1 - 2002
N2 - We studied the mechanisms of K(+) transport in cells from isolated and perfused collecting tubules and ducts from the mesonephric kidney of the toad Bufo bufo. Cells were impaled with microelectrodes across the basal cell membrane. The basolateral membrane potential (V(bl)) depolarized upon change of bath [K(+)] from 3 to 20 mmol l(-1) demonstrating a large K(+) conductance in this membrane. In collecting tubules and collecting ducts a V(bl) of -66+/-2 mV and -74+/-4 mV depolarized by 30+/-2 mV and 36+/-3 mV, respectively (N=23; 15). The K(+) channel inhibitor Ba(2+) (1 mmol l(-1)) inhibited the basolateral K(+) conductance and depolarized a V(bl) of -64+/-4 mV by 30+/-6 mV (N=8). Luminal K(+) steps (3 to 20 mmol l(-1)) demonstrated a K(+) conductance in the apical cell membrane. In collecting tubules and collecting ducts a V(bl) of -70+/-3 mV and -73+/-3 mV depolarized by 11+/-3 mV and 16+/-3 mV, respectively (N=11; 11). This conductance could also be inhibited by Ba(2+), which depolarized a V(bl) of -71+/-5 mV by 9+/-3 mV (N=5). The pump inhibitor ouabain (1 mmol l(-1)) depolarized V(bl), but addition of furosemide to bath solution did not affect V(bl). The [K(+)] in urine varied from 1.3 to 22.8 mmol l(-1). In conclusion, we propose that the collecting duct system of B. bufo secretes K(+) into the urine via luminal K(+) channels.
AB - We studied the mechanisms of K(+) transport in cells from isolated and perfused collecting tubules and ducts from the mesonephric kidney of the toad Bufo bufo. Cells were impaled with microelectrodes across the basal cell membrane. The basolateral membrane potential (V(bl)) depolarized upon change of bath [K(+)] from 3 to 20 mmol l(-1) demonstrating a large K(+) conductance in this membrane. In collecting tubules and collecting ducts a V(bl) of -66+/-2 mV and -74+/-4 mV depolarized by 30+/-2 mV and 36+/-3 mV, respectively (N=23; 15). The K(+) channel inhibitor Ba(2+) (1 mmol l(-1)) inhibited the basolateral K(+) conductance and depolarized a V(bl) of -64+/-4 mV by 30+/-6 mV (N=8). Luminal K(+) steps (3 to 20 mmol l(-1)) demonstrated a K(+) conductance in the apical cell membrane. In collecting tubules and collecting ducts a V(bl) of -70+/-3 mV and -73+/-3 mV depolarized by 11+/-3 mV and 16+/-3 mV, respectively (N=11; 11). This conductance could also be inhibited by Ba(2+), which depolarized a V(bl) of -71+/-5 mV by 9+/-3 mV (N=5). The pump inhibitor ouabain (1 mmol l(-1)) depolarized V(bl), but addition of furosemide to bath solution did not affect V(bl). The [K(+)] in urine varied from 1.3 to 22.8 mmol l(-1). In conclusion, we propose that the collecting duct system of B. bufo secretes K(+) into the urine via luminal K(+) channels.
M3 - Journal article
C2 - 11916986
VL - 205
SP - 897
EP - 904
JO - Journal of Experimental Biology
JF - Journal of Experimental Biology
SN - 0022-0949
IS - Pt 7
ER -
ID: 8569888