Intracellular Recordings

Overview:

Electrophysiology is the study of the electrical properties of biological cells and tissues. It involves measurements of voltage change or electrical current flow on a wide variety of scales from single ion channel proteins to whole tissues like the heart. In neuroscience, it includes measurements of the electrical activity of neurons, and particularly action potential activity. Intracellular recordings involve voltage or current measurements across a membrane of a cell.

 

Method:

Intracellular recordings involve measuring voltage and/or current across the membrane of a cell. There are many intracellular recording techniques including:

• Sharp Electrode Technique – measures the potential inside the cell membrane with a sharp electrode (glass micropipette with a smaller pore). This, by definition, is a whole cell recording since the electrolyte solution in the electrode is in contact with the intracellular fluid. There are two types of Sharp Electrode Clamping:
  • Voltage Clamp – measures the ionic current across a cell's membrane when the membrane potential is held at a constant. Sharp Electrode Voltage Clamping can be further split into two groups:
    • Single Electrode Voltage Clamping (SEVC) and
    • Two Electrode Voltage Clamping (TEVC)
  • Current Clamp - measures the membrane potential changes when injecting a constant current into a cell through the recording electrode.

Note: SEVC is generally only considered when the cells are too small for TEVC. TEVC is most commonly used on large cells such as oocytes and is also referred to as Oocyte clamping.

• Patch Clamp – measures voltage or current across ion channels using a blunt tip micropipette
• Epithelial Voltage Clamping (and Ussing Chambers) - measures the transport of electrolytes, non-electrolytes and H₂0 across an epithelial membrane. It is typically comprised of an Ussing chamber and perfusion system, an amplifier and a data acquisition system.

For more information on various applications please visit:

• Neurophysiology application page
• Extracellular Recordings application page
• Patch & Voltage Clamping application page
• Evoked Potentials application page
• Microneurography application page
   

Software:

The LabChart Advantage:

(may require additional Modules and Extensions)

• Sample up to 200,000 Hz in a single channel (up to 400,000 Hz aggregate) using the 35 series PowerLabs
• Smoothing, Absolute Value, Integration and RMS Arithmetic calculations for quantification of neural activity
• Spectrum feature for online or offline determination of the power and frequency components of recorded signals
• Cyclic measurements for calculating firing Frequency, Period, and action potential Count
• Scope View for spike-triggered averaging and the overlay of evoked responses
• Telegraph Extension for correct scale display of data after a hardware gain change
• Peak Analysis Module for analysis of peak heights, half-widths, latency periods, population spike heights, rise times and areas
• Provides the ability to record, display and analyze any high frequency signal that is time-locked to a stimulus
• Generates stimuli of differing intensities and waveform structures (i.e. single-pulse, multiple pulse, simple ramps) and control an external stimulator using the analog output on the front of the PowerLab.

LabChart

LabChart software (for Windows and Macintosh) combines the familiar simplicity of a traditional strip chart recorder with the powerful analysis features of a digital acquisition system. LabChart software and a PowerLab data acquisition unit provide data integrity, easy selection of hardware settings, powerful online and offline analysis, procedure automation, seamless extraction of experimental data and flexible display options. Acquisition and analysis capabilities can be further increased with LabChart Extensions and LabChart Modules. LabChart Modules are available as part of LabChart Pro and LabChart Extensions are free for download from the website for existing LabChart users.

Useful LabChart Extensions

• Event Manager (Win): Allows the user to monitor user defined events online using different criteria, and to perform a variety of user defined actions..
• Evoked Response (Mac): This Extension analyzes physiological responses to a stimulus (evoked response experiments). A number of response parameters can be measured and logged to the Data Pad. This process can be automated to analyze a series of stimuli/response cycles. Physiological responses of neurons to stimuli can be measured include value, latency, peak height, half-width, latency to peak, slope, population spike height and population spike area.
• Peak Parameters (Mac): Allows the user to determine a number of parameters for an individual peak. Parameters calculated include peak height, width, slope and various time parameters. It is useful for determining parameters of action potentials such as cardiac potentials, EPSP and IPSP.
• Export MATLAB (Mac or Win): Allows LabChart for Windows files to be saved and exported as MATLAB compatible files.
• Translate Axon (Win): Allows the user to save LabChart files in the ABF (Axon binary format) which can be read by pClamp
• Translate Binary (Win): Translate Binary is a LabChart Extension which allows LabChart for Windows files to be saved and exported in a simple binary format. Translate Binary can import documents that have either been exported from LabChart or generated by another application.
• Translate EDF (Win): Allows LabChart to save data as an EDF file, and to read EDF files. Translate EDF does not support the EDF+ format.
• Telegraph (Win): Makes use of the gain-telegraph output from an electrophysiological amplifier to continue to display data at the correct scale after a gain change. The Telegraph Extension uses the gain telegraph voltage from the amplifier to automate the display of electrophysiological data in LabChart, so that the correct units and scale are used.

Peak Analysis Module

The Peak Analysis Module (Windows) automatically detects and analyses multiple, non-overlapping peaks in recorded waveforms.

Features and benefits include:

• View automatically detected peaks with highlighted parameter markers, values and peak areas in the Peak Analysis View.
• Log calculated peak parameters to a table. Easily export parameters from the table into other programs.
• Select from the default analysis settings available for general and specific signal types.
• Customizable detection and calculation settings to suit your application or waveform.

Scope View

By providing digital oscilloscope feature Scope View (LabChart Windows) facilitates recording and viewing consecutive sweeps of data. These sweeps, or pages, can be overlaid and averaged. The signal averaging functions are necessary to extract the evoked response from background noise. There are several powerful features in Scope View that enhance analysis and display including:

• Create pages or sweeps from Comments in Chart View in addition to block mode and Event Mode.
• Use the new 3D Depth and Saturation Overlay feature in the Scope Overlay Options to help distinguish overlaid traces.
• Alter the active trace and overlay trace colors.
• Change the display background to black for better contrast.
  

GLP and 21 CFR Part 11

For those researchers working within a laboratory requiring GLP and 21 CFR Part 11 compliance the GLP Client and GLP Server are available for use with LabChart (Windows only) and PowerLab data acquisition systems. For more information, visit the Good Laboratory Practice application page or contact your nearest ADInstruments representative.

Hardware:

PowerLab Data Acquisition Systems

The PowerLab is a high-performance data acquisition unit capable of recording at speeds of up to 400,000 samples per second continuously to disk (aggregate). PowerLab units are compatible with instruments, signal conditioners and transducers supplied by ADInstruments, as well as many other third-party companies. In addition to standard single-ended BNC inputs, 4 differential Pod ports are also available for direct connection of Pod signal conditioners and appropriate transducers. Research PowerLab units include:

• PL3504 PowerLab 4/35 - 4 Channels
• PL3508 PowerLab 8/35 – 8 Channels
• PL3516 PowerLab 16/35 – 16 Channels

Research Systems

PL3508B74-V Intracellular Recording System includes:

• PL3508 PowerLab 8/35 (LabChart software)
• MLS260 LabChart Pro software
• MLA190 19" Rack Adapter
• IE-210-V Intracellular Electrometer Amplifier
• ESP/W-F15N E Series Electrode Holder (Str, Ag-AgCl Pellet & Wire, 1.5 mm)

Instruments

Intracellular Amplifiers

• IE-210-V Intracellular Electrometer
• IE-251A-V Intracellular Low Cost Electrometer
• AM3100-V-C Intracellular Amplifier (with headstage)
• IX1 Single Channel Intracellular Preamplifier

Stimulators

• STG4004 4 Channel Stimulus Generator
• STG4008 8 Channel Stimulus Generator 
• ML1001 Electronic Stimulator
• ML1101 Stimulus Isolator

Transducers and Accessories

Electrode Holders

For the complete range of electrode holders click here:

• ESP-F10N E Series Electrode Holder (Str, Ag-AgCl Pellet, 1.0 mm)
• ESP-F12N E Series Electrode Holder (Str, Ag-AgCl Pellet, 1.2 mm)
• ESP-F15N E Series Electrode Holder (Str, Ag-AgCl Pellet, 1.5 mm)
• ESP-F20N E Series Electrode Holder (Str, Ag-AgCl Pellet, 2.0 mm)
• ERP-M10N E Series Electrode Holder (90°, Ag-AgCL Pellet, 1.0 mm)
• ERP-M12N E Series Electrode Holder (90°, Ag-AgCL Pellet, 1.2 mm)
• ERP-M15N E Series Electrode Holder (90°, Ag-AgCL Pellet, 1.5 mm)
• ERP-M20N E Series Electrode Holder (90°, Ag-AgCL Pellet, 2.0 mm)
• ESP/W-F10N E Series Electrode Holder (Str, Ag-AgCl Pellet & Wire, 1.0 mm)
• ESP/W-F12N E Series Electrode Holder (Str, Ag-AgCl Pellet & Wire, 1.2 mm)
• ESP/W-F15N E Series Electrode Holder (Str, Ag-AgCl Pellet & Wire, 1.5 mm)
• ESP/W-F20N E Series Electrode Holder (Str, Ag-AgCl Pellet & Wire, 2.0 mm)

Note: Selection is based on the outer diameter of user’s glass electrode

Headstages

• 2100W Headstage for IE-210-V
• 2510W Headstage for IE-251A-V
• 8024-15 Extracellular Headstage (for use with intracellular amplifiers such as IX1)
• 8024-7001 Dual Intracellular & Extracellular Headstage (for use with intracellular amplifiers such as IX1)

Buzz Control Accessories

• RB-1 Remote Buzz Control for IE-210-V
• BB-15 Breakaway Box for IE-210-V
• BUZ-1 Universal Buzz Box (attaches to any intracellular preamplifier such as IX1)
• BUZZ Foot Pedal

Relation of Blood Pressure Quantitative Trait Locus on Rat Chromosome 1 to Hyperactivity of Rostralventrolateral Medulla
Iigaya K, Kumagai H, Nabika T, Harada Y, Onimaru H, Oshima N, Takimoto C, Kamayachi T, Saruta T, Itoh H, Hypertension, 42-48, 2009

Spontaneous transient depolarizations in lymphatic vessels of the guinea pig mesentery: pharmacology and implication for spontaneous contractility
von der Weid P Y, Rahman M, Imtiaz M S, van Helden D F, American Journal of Physiology: Heart and Circulatory Physiology, H1989–H2000, 2008

D1/D2-dopamine receptor agonist dihydrexidine stimulates inspiratory motor output and depresses medullary expiratory neurons
Lalley PM, American Journal of Physiology: Regulatory, Integrative and Comparative Physiology, R1829-R1836, 2009