Vasopressin-dependent control of basolateral Na/H-exchange in highly differentiated A6-cell monolayers.
We have used a well-differentiated A6-cell preparation (A6-C1) to study cellular location and vasopressin control of Na/H-exchange activity. After cell acidification, cell pHi (measured by BCECF-fluorescence) only recovered by the addition of Na medium to the basolateral cell surface; this pHi recovery was inhibited by dimethylamiloride (2 microM) consistent with basolateral location of Na/H-exchange activity. Addition of vasopressin produced stimulation of Na/H-exchange activity and increased the affinity of the exchanger for Na+. Stimulation of Na/H exchange was mimicked by pharmacological activation of protein kinase A (forskolin, 8-Br-cAMP) and not by pharmacological activation of protein kinase C (TPA). It is concluded that basolaterally located Na/H-exchange in A6-C1 cells is activated by vasopressin.
Guerra
L
L
Department of Physiology, University of Zürich, Switzerland.
Casavola
V
V
Vilella
S
S
Verrey
F
F
Helmle-Kolb
C
C
Murer
H
H
D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004789:Enzyme Activation; D004847:Epithelial Cells; D004848:Epithelium / Q000737:chemistry / Q000502:physiology; D005453:Fluorescence; D006863:Hydrogen-Ion Concentration; D007684:Kidney Tubules / Q000737:chemistry / Q000166:cytology* / Q000502:physiology; D017923:Sodium-Hydrogen Exchangers / Q000032:analysis / Q000502:physiology*; D014667:Vasopressins / Q000494:pharmacology*; D014982:Xenopus laevis
D017923:Sodium-Hydrogen Exchangers; D014667:Vasopressins; D017868:Cyclic AMP-Dependent Protein Kinases