Characterization of voltage-gated sodium-channel blockers by electrical stimulation and fluorescence detection of membrane potential.
Voltage-gated ion channels regulate many physiological functions and are targets for a number of drugs. Patch-clamp electrophysiology is the standard method for measuring channel activity because it fulfils the requirements for voltage control, repetitive stimulation and high temporal resolution, but it is laborious and costly. Here we report an electro-optical technology and automated instrument, called the electrical stimulation voltage ion probe reader (E-VIPR), that measures the activity of voltage-gated ion channels using extracellular electrical field stimulation and voltage-sensitive fluorescent probes. We demonstrate that E-VIPR can sensitively detect drug potency and mechanism of block on the neuronal human type III voltage-gated sodium channel expressed in human embryonic kidney cells. Results are compared with voltage-clamp and show that E-VIPR provides sensitive and information-rich compound blocking activity. Furthermore, we screened approximately 400 drugs and observed sodium channel-blocking activity for approximately 25% of them, including the antidepressants sertraline (Zoloft) and paroxetine (Paxil).
Huang
Chien-Jung
CJ
Vertex Pharmaceuticals Incorporated, 11010 Torreyana Road, San Diego, California 92121, USA.
Harootunian
Alec
A
Maher
Michael P
MP
Quan
Catherine
C
Raj
Christopher D
CD
McCormack
Ken
K
Numann
Randal
R
Negulescu
Paul A
PA
González
Jesús E
JE
D002478:Cells, Cultured; D015195:Drug Design; D004558:Electric Stimulation / Q000379:methods*; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology*; D008856:Microscopy, Fluorescence / Q000379:methods*; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques / Q000379:methods; D004364:Pharmaceutical Preparations / Q000008:administration & dosage*; D015222:Sodium Channels / Q000187:drug effects / Q000502:physiology*
D004364:Pharmaceutical Preparations; D015222:Sodium Channels