Fluorescence imaging of electrically stimulated cells.
Designing high-throughput screens for voltage-gated ion channels has been a tremendous challenge for the pharmaceutical industry because channel activity is dependent on the transmembrane voltage gradient, a stimulus unlike ligand binding to G-protein-coupled receptors or ligand-gated ion channels. To achieve an acceptable throughput, assays to screen for voltage-gated ion channel modulators that are employed today rely on pharmacological intervention to activate these channels. These interventions can introduce artifacts. Ideally, a high-throughput screen should not compromise physiological relevance. Hence, a more appropriate method would activate voltage-gated ion channels by altering plasma membrane potential directly, via electrical stimulation, while simultaneously recording the operation of the channel in populations of cells. The authors present preliminary results obtained from a device that is designed to supply precise and reproducible electrical stimuli to populations of cells. Changes in voltage-gated ion channel activity were monitored using a digital fluorescent microscope. The prototype electric field stimulation (EFS) device provided real-time analysis of cellular responsiveness to physiological and pharmacological stimuli. Voltage stimuli applied to SK-N-SH neuroblastoma cells cultured on the EFS device evoked membrane potential changes that were dependent on activation of voltage-gated sodium channels. Data obtained using digital fluorescence microscopy suggests suitability of this system for HTS.
Burnett
Paul
P
Johnson & Johnson Pharmaceutical Research and Development, LLC, Raritan, NJ 08869, USA.
Robertson
Janet K
JK
Palmer
Jeffrey M
JM
Ryan
Richard R
RR
Dubin
Adrienne E
AE
Zivin
Robert A
RA
D002118:Calcium / Q000494:pharmacology; D045744:Cell Line, Tumor; D002468:Cell Physiological Phenomena / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004553:Electric Conductivity; D004558:Electric Stimulation; D005453:Fluorescence; D006801:Humans; D007204:Indium / Q000494:pharmacology; D020128:Inhibitory Concentration 50; D015640:Ion Channel Gating / Q000187:drug effects; D008564:Membrane Potentials / Q000187:drug effects; D018408:Patch-Clamp Techniques; D015222:Sodium Channels / Q000378:metabolism; D013779:Tetrodotoxin / Q000494:pharmacology; D013997:Time Factors; D014701:Veratridine / Q000494:pharmacology
D015222:Sodium Channels; D007204:Indium; D013779:Tetrodotoxin; D014701:Veratridine; D002118:Calcium