Tetrodotoxin citrate ttx

Chemicals including lithium chloride (LiCl), picrotoxin, strychnine hydrochloride (strychnine), and chemicals for ACSF were purchased from Sigma-Aldrich (St. Louis, MO, USA). Tetrodotoxin citrate (TTX), DL-AP5 (AP5), and CNQX disodium salt (CNQX) were purchased from Tocris Bioscience (Avonmouth, Bristol, UK). Stocks were diluted (usually by 1000 times) to a working concentration in ACSF before bath application.

All drugs were obtained from Sigma-Aldrich (St. Louis, MO, USA) except tetrodotoxin citrate (TTX), kynurenic acid, and 6,7-dinitroquinoxaline-2,3-dione disodium salt (DNQX), which were purchased from Tocris Bioscience (Ellisville, MO, USA). Stock solutions of bicuculline methyl bromide, allopregnanolone, and picrotoxin were dissolved in DMSO, while stock solutions of kynurenic acid and mefenamic acid were made up in 0.1 M sodium hydroxide. The final bath concentrations of these solvents did not exceed 0.1% of the recording solutions. Stock solutions of DNQX, phenobarbital sodium salt, chlordiazepoxide hydrochloride, d-2-amino-5-phosphonovalerate (AP5), tetraethylammonium chloride (TEA), and strychnine hydrochloride were made up in bath solution. All drug solutions were made fresh immediately prior to experiments except for TTX, which was stored at −20 °C in small aliquots of stock solution made up in deionized water. Drugs were applied directly to cells under voltage-clamp from the tip of a 250-μm pipette. Fresh bath solution was also perfused through the bath (at 1–2 mL/min) using a gravity-feed system to prevent any build-up of drug solutions in the bath. At least 2 or 3 control responses were recorded before the addition of any drug. Drugs were washed out once a stable effect was observed and control responses then re-established before further drug applications.