Measurement of intracellular Na+ concentration by a Na+-sensitive fluorescent dye, sodium-binding benzofuran isophthalate, in porcine adrenal chromaffin cells--usage of palytoxin as a Na+ ionophore.
Palytoxin was found to equilibrate sodium ions (Na+) across the cell membrane much faster than dose gramicidin, which has been frequently used to calibrate the intracellular Na+ concentration ([Na+]in), in cells treated with a Na+-sensitive fluorescent dye, sodium-binding benzofuran isophthalate (SBFI). Palytoxin was capable of equilibrating Na+ in cells treated with SBFI-acetoxymethyl ester (SBFI-AM) and in voltage-clamped cells loaded with SBFI through a patch pipette. Nicotine caused a dose-dependent increase in ([Na+]in) in porcine adrenal chromaffin cells treated with SBFI-AM and caused a simultaneous increase in [Na+]in and inward current in the voltage-clamped cells loaded with SBFI. Palytoxin has an advantage of calibrating ([Na+]in) in a shorter time than dose gramicidin because of its powerful ionophoretic activity.
Ito
S
S
Laboratory of Pharmacology, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan. sito@vetmed.hokudai.ac.jp
Ohta
T
T
Kadota
H
H
Kitamura
N
N
Nakazato
Y
Y
D000178:Acrylamides / Q000494:pharmacology*; D000818:Animals; D001572:Benzofurans / Q000494:pharmacology*; D002138:Calibration; D002478:Cells, Cultured; D019439:Chromaffin Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D003064:Cnidarian Venoms; D003956:Dialysis; D004353:Drug Evaluation, Preclinical; D004988:Ethers, Cyclic / Q000494:pharmacology*; D005456:Fluorescent Dyes; D006096:Gramicidin / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects; D009538:Nicotine / Q000494:pharmacology*; D018408:Patch-Clamp Techniques; D012964:Sodium / Q000378:metabolism*; D013552:Swine; D000095702:Polyether Toxins
D000178:Acrylamides; D001572:Benzofurans; D003064:Cnidarian Venoms; D004988:Ethers, Cyclic; D005456:Fluorescent Dyes; D006096:Gramicidin; D007476:Ionophores; D009538:Nicotine; D012964:Sodium; C061665:sodium-binding benzofuran isophthalate; C010272:palytoxin; D000095702:Polyether Toxins