TY - JOUR
T1 - Where have all the Na+ channels gone? In search of functional ENaC in exocrine pancreas.
AU - Novak, Ivana
AU - Hansen, Mette R
N1 - Keywords: Amiloride; Animals; Epithelial Sodium Channel; Female; Glucocorticoids; Membrane Potentials; Microelectrodes; Mineralocorticoids; Pancreas; Pancreatic Ducts; Patch-Clamp Techniques; Perfusion; Rats; Rats, Wistar; Secretin; Sincalide; Sodium; Sodium Channels
PY - 2002
Y1 - 2002
N2 - Many epithelia express specific Na(+) channels (ENaC) together with the cystic fibrosis regulator (CFTR) Cl(-) channels. Pancreatic ducts secrete HCO(3)(-)-rich fluid and express CFTR. However, the question whether they possess ENaC has not been consistently addressed. The aim of the present study was to investigate if pancreatic ducts express functional ENaC. Membrane voltages (V) of ducts isolated from rat pancreas were measured with microelectrodes or whole-cell patch-clamp technique. Amiloride and benzamil given from bath or luminal sides did not hyperpolarize V. Lowering of extracellular Na(+) concentrations had effects that were not consistent with a simple Na(+) conductance, but rather with a Na(+)/Ca(2+) exchange. Acute or long-lasting treatment of pancreatic ducts with mineralocorticoids had no effect on V of unstimulated or secretin-stimulated preparations. Furthermore, pre-treatment of animals with glucocorticoids had no effect on pancreatic fluid secretion evoked from ducts, or from acini. Hence, our study shows that pancreas especially pancreatic ducts do not express functional ENaC.
AB - Many epithelia express specific Na(+) channels (ENaC) together with the cystic fibrosis regulator (CFTR) Cl(-) channels. Pancreatic ducts secrete HCO(3)(-)-rich fluid and express CFTR. However, the question whether they possess ENaC has not been consistently addressed. The aim of the present study was to investigate if pancreatic ducts express functional ENaC. Membrane voltages (V) of ducts isolated from rat pancreas were measured with microelectrodes or whole-cell patch-clamp technique. Amiloride and benzamil given from bath or luminal sides did not hyperpolarize V. Lowering of extracellular Na(+) concentrations had effects that were not consistent with a simple Na(+) conductance, but rather with a Na(+)/Ca(2+) exchange. Acute or long-lasting treatment of pancreatic ducts with mineralocorticoids had no effect on V of unstimulated or secretin-stimulated preparations. Furthermore, pre-treatment of animals with glucocorticoids had no effect on pancreatic fluid secretion evoked from ducts, or from acini. Hence, our study shows that pancreas especially pancreatic ducts do not express functional ENaC.
U2 - 10.1016/S0005-2736(02)00598-9
DO - 10.1016/S0005-2736(02)00598-9
M3 - Journal article
C2 - 12421547
SN - 0304-4165
VL - 1566
SP - 162
EP - 168
JO - BBA General Subjects
JF - BBA General Subjects
IS - 1-2
ER -