Anionic selectivity sequence of the Cl(-)-H+ symporter in the synaptosomal preparation from rat brain cortex.
The Na(+)/H(+) exchanger has been the only unequivocally demonstrated H(+)-transport mechanism in the synaptosomal preparation. We had previously suggested that a Cl(-)-H(+) symporter (in its acidifying mode) is involved in cytosolic pH regulation in the synaptosomal preparation. Supporting this suggestion, we now show that: (1) when synaptosomes are transferred from PSS to either gluconate or sulfate solutions, the Fura-2 ratio remains stable instead of increasing as it does in 50 mM K solution. This indicates that these anions do not promote a plasma membrane depolarization. (2) Based in the recovery rate from the cytosolic alkalinization, the anionic selectivity of the Cl(-)-H(+) symporter is NO(3)(-) > Br(-) > Cl(-) >> I(-) = isethionate = sulfate = methanesulfonate = gluconate. (3) PCMB 10 muM inhibits the gluconate-dependent alkalinization by 30 +/- 6%. (4) Neither Niflumic acid, 9AC, Bumetanide nor CCCP inhibits the recovery from the cytosolic alkalinization.
Torres
M L
ML
Departamento de Fisiología y Farmacología, Facultad de Medicina, Universidad Autónoma de San Luis Potosi, Av. V. Carranza 2405, San Luis Potosi, S.L.P., 78210, Mexico.
Ortega
F
F
Cuaranta
I
I
González
J
J
Sanchez-Armass
S
S
D000595:Amino Acid Sequence; D000818:Animals; D000838:Anions / Q000378:metabolism*; D017920:Antiporters / Q000235:genetics* / Q000378:metabolism*; D001190:Arylsulfonates / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D002034:Bumetanide / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D005942:Gluconates / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007476:Ionophores / Q000378:metabolism; D009544:Niflumic Acid / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D051381:Rats; D049994:Sodium Potassium Chloride Symporter Inhibitors / Q000378:metabolism; D013431:Sulfates / Q000378:metabolism; D013574:Synaptosomes / Q000378:metabolism*
D000838:Anions; D017920:Antiporters; D001190:Arylsulfonates; D005456:Fluorescent Dyes; D005942:Gluconates; D007476:Ionophores; D049994:Sodium Potassium Chloride Symporter Inhibitors; D013431:Sulfates; C114260:hydrogen-chloride symporter; D002034:Bumetanide; D009544:Niflumic Acid; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; C005047:pyranine; C030691:gluconic acid; D011188:Potassium; D002118:Calcium