APPLICATIONS

See How Our Products Are Used In a Wide Variety Of Applications.

  1. 1
    Two Electrode Voltage Clamp of Oocytes

    Two Electrode Voltage Clamp of Oocytes

    The voltage clamp technique is a method that allows ion flow across the cell membrane to be measured as an electric current as the transmembrane potential is held under constant experimental control with a feedback amplifier. Ion channels expressed in Xenopusoocytes can be studied using the two-microelectrode voltage clamp. The membrane of the oocyte is penetrated by two microelectrodes, one for voltage sensing and one for current injection. The membrane potential as measured by the voltage-sensing electrode and a high input impedance amplifier is compared with a command voltage, and the difference is brought to zero by a high gain feedback amplifier. The injected current is monitored via a current-to voltage converter to provide a measure of the total membrane current.

    Equipment:

    • npi TEC-05X-CC or npi TEC-10CX
    • KS 9211 table
    • ALA PPH-0P-BNC holders
    • ALA VC38 with ALA PR-10 and ALA VWK
    • npi ScreenTool Package
    • MCS Roboocyte
    • MCS HiClamp
  2. 2
    Macropatch Recording

    Macropatch Recording

    The technique for macropatching is similar to tight seal single-channel recording. The electrodes are pulled to larger tip diameters than would be used for single-channel recording; however, with single-channel recording, following initial contact with the membrane, suctions is applied to form an electrically and mechanically tight seal in gigohm range. Recordings can be obtained in the cell-attached configuration or from inside-out or outside-out membrane patches.

    The objective, for many laboratories using this technique, is to record from specific areas of the membrane relative to known specializations, for example, the distribution of the ion channels in the pre- or postsynaptic membrane, dendritic vs somatic membranes. Macropatch electrodes have resistances in the range 0.5-3MOhms and are in the order of 2-8um diam. Our range of HEKA and NPI patch clamp amplifiers are particularly suited for such recordings.

    Equipment:

    • HEKA EPC-10
    • KS 9100 series table
    • ALA VC3 with  ALA PR-10 and ALA MLF or ALA OctaFlow
    • ALA MS Chambers
    • HEKA PatchMaster
    • ALA HSSE-2/3
  3. 3
    Single-Channel Recording

    Single-Channel Recording

    Single-channel recording is achieved by pressing a fire-polished glass pipette, which has been filled with a suitable electrolyte solution, against the surface of a cell and applying light suction. Under such conditions, the glass pipette and the cell membrane will be less than 1 nm apart. The tighter the seal will have two advantages, 1) better electrical isolation of the membrane patch and 2) a high seal resistance reduces the current noise of the recording, permitting good time resolution of single channel currents, currents whose amplitude is in the order of 1 pA. Classically, three different configurations of the patched membrane can be used for single-channel recording: cell-attached, outside-out and inside-out patches. Cell-attached configuration contacts the cell membrane forming a gigaohm seal. Long-term stable recordings with low background noise can be performed in this configuration with minimal disruption to the intracellular milieu. For the outside-out configuration, the external surface of the patch is exposed to the external recording media. Offering the opportunity to repetitively expose the channels to different drugs and at various concentrations. In the inside-out patch configuration, it is the internal face of the membrane that is exposed to the external solution. This provides access to intracellular receptor binding sites and also enables studies of intracellular signaling pathways.

    It is now possible to record single-channel current activity from many cell types, that is, from mammalian species, insects, invertebrates and also plants. The recording of single-channel currents enables detailed kinetic analyses of native and recombinant ion channels, including those that have been subject to natural or intended mutations to their structure.

    Equipment:

    • HEKA EPC-10
    • KS 9100 series table
    • ALA VC3-8 with ALA PR-10 and ALA MLF or ALA OctaFlow
    • ALA MS Chambers
    • HEKA PatchMaster
    • Bruxton TAC
  4. 4
    Whole-Cell Recording

    Whole-Cell Recording

    Whole cell recording is the most commonly used configuration of the patch clamp technique. It is achieved by rupturing the patch of membrane isolated by the patch pipette bringing the cell interior into contact with the pipette interior. Using the whole cell patch clamp design of experiment one can then record the electrical activity of the entire cell via several modes. Voltage clamp, where the potential difference across the cell membrane is controlled and current measured, or current clamp, controlling the current and measuring the voltage across the membrane are the two main modes of whole cell recording. These recording configurations are very powerful techniques in the study of ion channel activity, aspects of neuronal behaviour and synaptic transmission. Our range of HEKA and NPI patch clamp amplifiers are perfect for carrying out whole cell patch clamp recordings.

    One major problem in whole recording is series resistance. Employing the ‘Discontinuous single electrode voltage clamp’ (dSEVC) technique is a very useful procedure to overcome the series resistance. The dSEVC separates the current injection from potential measurement in time, by rapid switching between a current injection mode and potential measuring mode. This ensures that no current passes through the resistor created at the pipette/cell interface during potential recording and completely eliminates series resistance artifacts. Provided the switching frequency between the current injection- and voltage measuring-mode is high enough, the plasma membrane can be clamped to a steady membrane potential. Our NPI SEC range of amplifiers are designed specifically for dSEVC being the fastest and most accurate single-electrode current – and voltage – clamp systems available.

    Equipment:

    • HEKA EPC-10
    • KS 9100 series table
    • ALA VC3 with ALA PR-10 and ALA MLF or ALA OctaFlow
    • ALA MS Chambers
    • HEKA PatchMaster
    • ALA HSSE-2/3
  5. 5
    Cardiac Rhythmicity

    Cardiac Rhythmicity

    The spontaneous depolarization and repolarization events that occurs in a repetitive and stable manner within the cardiac muscle is often abnormal or lost in cases of cardiac dysfunction or cardiac failure. The underlaying mechanisms of this rhythmicity are based on the myriad of voltage dependent ion channels found in cardiac myocytes. These ion channels can then be studied at the single channel, single cell or tissue level using various techniques and equipment supplied by ALA Scientific Instruments.

    The use of the patch clamp technique is very powerful at the single channel and single cell (whole cell) level. Such amplifiers as the manufactured by HEKA and NPI are ideal. In addition, ALA Scientific Instruments range of perfusion systems make cardiac experiments very easy. At the tissue level, MCS multielectrode arrays are capable of recording from distinct regions of cardiac slices simultaneously.

    In Vitro Cell and Tissue Preparations

    Equipment:

    • MCS MEA60-BC system
    • ALA VC3-4
    • ALA VWK

    In Vivo Multielectrode Recording

    Equipment:

    • MCS ME-32-System
    • MCS FlexArray

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