QX 314 chloride

Membrane impermeable Na⁺ channel blocker. A quaternary derivative of lidocaine. Displays anesthetic properties. Active in vivo. QX 314 bromide also available.

#Figure 1: QX 314 inhibition of action potentials in rat CA1 pyramidal neurones during dendritic plateau potentials

QX 314 is a membrane impermeable Na⁺ channel blocker commonly used to inhibit action potential formation. QX 314 from Hello Bio inhibits the ability for action potentials to generate in two different cells during dendritic plateau potentials at 1mM (see Fig 1 above).

#Protocol 1: Evoked plateau potentials in rat CA1 pyramidal neurones

• Pyramidal neurones from adult Wistar rats were patched in CA1 using a KMeSO4 internal solution with and without the addition of 1mM QX 314 (HB1030).
• Cells were first held in V_clamp at -70mV for 10 minutes to wash out LTP before being transferred to I_clamp (again at -70mV) where they were stimulated at a high stimulation intensity to generate plateau potentials.
• Stimulation consisted of one single stimulation followed 400ms later by 5 stimulations at 100Hz.
• Experiments took place in the presence of the GABA_B antagonist GCP-55845 (1μM, HB0960) and 50µM PTX.
• Throughout the experiment input current was adjusted to maintain the cell at -70mV ± 0.5mV.
• Data is shown from two separate cells.