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Control of the amiloride‐sensitive Na+ current in mouse salivary ducts by intracellular anions is mediated by a G protein.
Author(s) -
Dinudom A,
Komwatana P,
Young J A,
Cook D I
Publication year - 1995
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1995.sp020899
Subject(s) - amiloride , conductance , pertussis toxin , gtp' , pipette , intracellular , chemistry , biophysics , patch clamp , cytosol , g protein , biochemistry , sodium , biology , enzyme , receptor , mathematics , organic chemistry , combinatorics
1. We have previously reported that the Na+ conductance in mouse intralobular salivary duct cells is controlled by cytosolic anions, being inhibited by high cytosolic concentrations of Cl‐ and NO3‐ but not of glutamate. In the present paper, we use whole‐cell patch‐clamp methods to investigate whether this anion effect is mediated by a G protein. 2. Inclusion of 100 mumol l‐1 GTP‐gamma‐S, a non‐hydrolysable GTP analogue, in the glutamate‐containing pipette solution, i.e. when the Na+ conductance is active, reduced the size of the Na+ conductance whereas inclusion of 100 mumol l‐1 GDP‐beta‐S, a non‐hydrolysable GDP analogue, had no effect. 3. Inclusion of 100 mumol l‐1 GDP‐beta‐S in the NO3(‐)‐containing pipette solution, i.e. when the Na+ conductance is inhibited, reactivated the conductance. Inclusion of 500 ng ml‐1 activated pertussis toxin in the NO3(‐)‐containing pipette solution had a similar effect on the Na+ conductance. 4. We conclude that the inhibitory effect of intracellular anions such as NO3‐ and Cl‐ on the amiloride‐sensitive Na+ conductance in mouse mandibular intralobular duct cells is mediated by a G protein sensitive to pertussis toxin.