Regulation of intracellular chloride concentration in rat lactotrophs: possible role of mitochondria.
Increasing evidence is accumulating for the involvement of chloride ions in the stimulus-secretion coupling of pituitary cells. We show that the mean intracellular chloride concentration [Cl-]i of rat lactotroph cells maintained in culture is high, close to 60 mM (59.4 mM), using the Cl- sensitive fluorescent probe 6-methoxy-N-(3-sulfopropyl) quinolinium (SPQ), coupled with whole-cell patch-clamp recordings. We demonstrate that this high level is correlated with the presence of mitochondrial stores of Cl- as shown by the release of Cl- in response to various metabolic inhibitors. We determine that CCP (50 microM) induces a mean [Cl-]i increase of 15.8+/-5.8 mM, using combined electrophysiology and microspectrofluorimetry methods. These data strongly suggest that cell metabolism, including the mitochondrial function, modulate [Cl-]i.
Garcia
L
L
Laboratoire de Neurophysiology, CNRS UMR 5543, University of Bordeaux II, France.
Rigoulet
M
M
Georgescauld
D
D
Dufy
B
B
Sartor
P
P
D000818:Animals; D002478:Cells, Cultured; D002712:Chlorides / Q000378:metabolism*; D004563:Electrochemistry; D005260:Female; D005456:Fluorescent Dyes; D007425:Intracellular Membranes / Q000187:drug effects; D007774:Lactation; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000378:metabolism*; D011806:Quinolinium Compounds; D051381:Rats; D017208:Rats, Wistar; D014475:Uncoupling Agents / Q000494:pharmacology
D002712:Chlorides; D005456:Fluorescent Dyes; D011806:Quinolinium Compounds; D014475:Uncoupling Agents; C052335:6-methoxy-N-(3-sulfopropyl)quinolinium