The Patch Clamp Technique

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The Patch Clamp Technique

• Chintan Hossain

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What is Patch Clamp?

• Use a pipette to pinch off a small region of
  membrane
• Provides access to
• the inside of the cell
• a small region of membrane
• Used to measure current through ion channels

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Types of patch clamp

• Whole Cell used by Peier et. al
• On-cell
• Inside Out
• Outside-Out

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Patch Clamp Procedure

• Press pipette against cell to form a tight seal
• Apply suction using the pipette to rupture the
  membrane

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Why Use Patch Clamp?

• Provides access to the inside of the cell
• Can insert an electrode into the cell
• Can change the intracellular fluid
• Creates a seal impermeable to ion flow
• High electrical resistance
• Allows one to measure current through ion
  channels vs. voltage, time, temperature, menthol
  concentration, etc.

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Voltage Clamp

• Technique used to hold membrane potential
  constant
• Ion currents tend to change the membrane
  potential
• Ion current depends on membrane potential
• Need to hold voltage constant to study ion
  currents

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Voltage Clamp Setup

• Hold voltage constant by injecting an opposing
  current
• Injected and membrane currents cancel out no
  net flow of charge
• Measure ion current by measuring injected current
• Uses the setup shown on the right

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The End