An iconographic program for computer-controlled whole-cell voltage clamp experiments

Dénes Budai, Lois J. Kehl, Georgetta I. Poliac, George L. Wilcox

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12 Citations (Scopus)

Abstract

A Macintosh-based system is described for performing instrument control, data acquisition and storage operations in single-electrode whole-cell voltage clamp experiments. The system consists of a commercially available voltage clamp amplifier, multifunction input/output (I/O) board, graphical programming language (LabVIEW 2) and custom built 'virtual instrument' (VI). The I/O board is capable of fast (up to 110 ksample/s) multichannel analog-to-digital (A/D) conversion with 12-bit resolution. It can control the gain settings of the clamp unit through digital I/O lines and generate the P/N leak subtraction protocol to eliminate the linear portion of capacitive currents using analog output voltages and gating pulses. Complete voltage clamp protocols can be implemented using the on-screen front panel controls of the VI. It enables the user to visualize the acquired data, to graph sets of current-voltage (I-V) relations or to fit single-exponential functions to one current trace. To evaluate the adequacy of whole-cell recording, the total membrane capacitance (Cm), the series resistance (Rs) and the time constant (τc) of the decay of the capacitive current are calculated using the single-exponential function fit to the data. The system is particularly well suited to the study of large quantities of transmembrane I-V relationships. Source code for the crucial elements of the VI as well as sample recordings from a cultured spinal cord neuron, illustrating system operation, are presented.

Original languageEnglish
Pages (from-to)65-74
Number of pages10
JournalJournal of Neuroscience Methods
Volume48
Issue number1-2
DOIs
Publication statusPublished - Jun 1993

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Keywords

  • Cultured neuron
  • Current-voltage relationship
  • LabVIEW 2
  • Leak subtraction
  • Macintosh
  • Membrane current
  • Voltage clamp

ASJC Scopus subject areas

  • Neuroscience(all)

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