Voltage Clamp Apparatus for Excitable Cells

Format

SOECS Senior Project Demonstration

Abstract/Artist Statement

The voltage clamp was first employed in Hodgkin and Huxley's classic studies of excitable membranes. A voltage clamp is implemented using a pair of electrodes inserted into a cell, one of which measures the transmembrane voltage, and the other of which passes current so as to maintain a constant voltage across the membrane. This apparatus and technique has been used to reveal multiple properties of ion channels, including: threshold potentials, ion-specific equilibrium potentials, ion current magnitudes and directions, the voltage dependence of ionic currents gated by various neurotransmitters, etc.We present a voltage clamp circuit designed to hold the transmembrane potential of an excitable cell at a user-determined command voltage, and that will monitor the current passing through the membrane ion channels in response to chemical activation. Our apparatus is being developed using electrical circuit models of neurons, and being tested on frog oocytes, which are commonly used to express a variety of membrane proteins such as voltage-gated or ligand-gated ion channels. We will demonstrate the application of voltage clamp methods to the study of the pharmacologic properties of neurotransmitters and drug compounds, as performed in Dr. Halliwell's lab.

Location

Pacific Geosciences Center

Start Date

30-4-2005 2:00 PM

End Date

30-4-2005 5:00 PM

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Apr 30th, 2:00 PM Apr 30th, 5:00 PM

Voltage Clamp Apparatus for Excitable Cells

Pacific Geosciences Center

The voltage clamp was first employed in Hodgkin and Huxley's classic studies of excitable membranes. A voltage clamp is implemented using a pair of electrodes inserted into a cell, one of which measures the transmembrane voltage, and the other of which passes current so as to maintain a constant voltage across the membrane. This apparatus and technique has been used to reveal multiple properties of ion channels, including: threshold potentials, ion-specific equilibrium potentials, ion current magnitudes and directions, the voltage dependence of ionic currents gated by various neurotransmitters, etc.We present a voltage clamp circuit designed to hold the transmembrane potential of an excitable cell at a user-determined command voltage, and that will monitor the current passing through the membrane ion channels in response to chemical activation. Our apparatus is being developed using electrical circuit models of neurons, and being tested on frog oocytes, which are commonly used to express a variety of membrane proteins such as voltage-gated or ligand-gated ion channels. We will demonstrate the application of voltage clamp methods to the study of the pharmacologic properties of neurotransmitters and drug compounds, as performed in Dr. Halliwell's lab.