Swelling and cAMP on hyperpolarization-activated Cl- conductance in rat Leydig cells.
We have used the whole cell patch-clamp technique to characterize changes in membrane conductance induced by osmotic swelling in mature rat Leydig cells dialyzed with ATP (control cells) or adenosine 3',5'-cyclic monophosphate (cAMP) plus ATP (cAMP cells). A spontaneous current activation occurs in both groups in isosmotic conditions (300/295 mosM in/out). This development is entirely counteracted in control cells and partly inhibited in cAMP cells by exposing them to a hyperosmotic (350 mosM) bath solution, and these currents increase again in a hyposmotic (205 mosM) bath solution. These currents are sensitive to 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid, a Cl- channel blocker. Taken together, the results indicate that, in the control cells (ATP alone) as well as in the presence of intracellular cAMP, osmotic swelling activates the background hyperpolarization-activated Cl- conductance, osmotic swelling and cAMP appearing to act synergistically.
Noulin
J F
JF
Laboratoire de Physiologie Animale, Unité de Recherche Associée Centre, National de la Recherche Scientifique 1869, Poitiers, France.
Fayolle-Julien
E
E
Desaphy
J F
JF
Poindessault
J P
JP
Joffre
M
M
D000818:Animals; D001834:Body Water / Q000378:metabolism*; D002712:Chlorides / Q000502:physiology*; D000242:Cyclic AMP / Q000494:pharmacology*; D004553:Electric Conductivity; D004594:Electrophysiology; D007038:Hypotonic Solutions / Q000494:pharmacology; D007700:Kinetics; D007985:Leydig Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D008297:Male; D009994:Osmolar Concentration; D018408:Patch-Clamp Techniques; D051381:Rats; D012996:Solutions / Q000494:pharmacology
D002712:Chlorides; D007038:Hypotonic Solutions; D012996:Solutions; D000242:Cyclic AMP