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Dose Response
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| ADInstruments provide both all-in-one and modular tissue-organ baths for the investigation of in vitro tissue preparations.
The organ bath is a traditional experimental set-up that has been used extensively to investigate the physiology and pharmacology of in vitro tissue preparations including: arterial rings, cervical strips, vas deferens, ileum, diaphragm, artery or colon, atrial or ventricular muscle as well as smooth and skeletal muscle.
Typically, these experiments study tissue contractions in response to particular concentrations of a pharmacological agent (a 'Dose Response' study). The tissue is suspended in a temperature-controlled chamber (the 'organ bath') and contractile function is recorded with either a force (isometric) or displacement (isotonic) transducer. The transducer is connected to a preamplifier (usually a bridge amplifier) which is connected to the PowerLab data acquisition system. ADInstruments provides a range of organ bath systems in multiple configurations to suit any research requirements.
PanLab Organ Baths
ADInstruments provides the following range of single and multiple (4, 8 and 16) organ bath systems manufactured by PanLab. - Preconfigured 4, 8 and 16 chamber Organ Bath Systems: These systems include multichamber organ baths, PowerLab, Bridge Amps, thermostatic controllers and isometric force transducers.
- The organ baths include micropositioners, gas diffusers, thermostat and water circulator. These systems incorporate automated controls for filling and emptying.
Organ bath tissue chambers are available in 5, 10, 25, and 50ml volumes. A variety of stainless steel or platinum stimulating electrodes are available.
Radnoti Organ Baths
Combining the excellence of Radnoti glassware and PowerLab data acquisition systems, ADInstruments provide a four chamber tissue organ bath that may be ordered separately or as part of the preconfigured 4, 8 and 16 Chamber Tissue-Organ Bath Systems. These complete research systems include a PowerLab, Bridge Amps, (MLT0201/RAD) Force Transducers (5 mg-25 g) and Thermo Bath/Circulator.
The Radnoti systems include innovative High-Tech Tissue Organ Baths (available in 5, 10, 25, 50, 100, 200 or 300ml), a 2L water-jacketed reservoir and perfusate tubing system, oxygenating bubbler and transducer positioners. All chambers contain a preheating coil within a thick water-jacketed wall in order to maintain the temperature of the physiological solution.
The organ baths are supplied complete with a glass hook tissue support and a removable oxygen disperser tube with a Teflon needle that is used to provide accurate gas adjustment.
Stimulating Electrodes
Radnoti also provides several combination tissue support rods/stimulating electrodes that are suitable for use in organ baths larger than 10 ml. A general guide for the use of these electrodes is as follows: Bridge Amplifiers
Most of the transducers that are used for isolated tissue studies require a suitable amplifier before the signal can be accurately recorded by PowerLab. Suitable amplifier units available from ADInstruments include the:
- Bridge Amp (ML221): Amplifier for connection of a single transducer.
- Quad Bridge Amp (ML224): Connects up to 4 transducers. Suitable for multiple chamber organ baths.
- Octal Bridge Amp (ML228): Connects up to 8 transducers.
- GP Amp: General purpose, non-isolated amplifier suitable for use with transducers that have a high signal output or high input impedance. May be required for some third-party transducers.
Transducers
Transducers available from ADInstruments for use with all organ baths include the:
Special Purpose Transducers
There are also many other brands of transducers that can be used with PowerLab for specialized applications. Some of these may also require special signal conditioners. Please consult with your nearest ADInstruments representative for advice on these transducers and their integration with ADInstruments' data acquisition units and signal conditioners.
Isotonic (Displacement) Transducers
In over 90% of cases an isometric transducer will be required. However, isotonic transducers may be required to measure displacement against a constant force. ADInstruments supply the High Grade isotonic transducer which is suitable for use with PanLab and Radnoti organ baths, with either GP Amp or Bridge Amps.
Stimulator
When using stimulating electrodes with the organ baths a suitable stimulator unit is required. Some stimulator units have a trigger input which can be connected to the PowerLab output allowing control of the frequency and timing of pulses from within the LabChart software. Ask your nearest ADInstruments representative for more information on a stimulator to best suit your research requirements.
DMT Wire Myographs
For microvascular studies involving small tubular structures (> 60 µm) such as veins and small arteries, complete single, dual and four-chamber wire myograph systems are available. A specialized single-chamber confocal myograph research system (for obtaining high resolution images of fluorescent dyes within living tissues) is also available. All systems include the myograph, PowerLab and accessories.
The DMT Normalization Module for Windows and Macintosh provides an easy method for the calculation of optimal pretension conditions for microvascular or any small tubular tissue research.
The module - automatically calculates tissue length
- provides online and offline determination of effective pressure
- calculates the pre-tension (micrometer setting) for normalization
The rationale and theory behind normalizing elastic tissues such as microvessels has been extensively investigated by Professor Michael Mulvany (for details see Mulvany MJ, Halpern, W Circulation Research 1977, 41: 19-26). Mulvany determined that the optimal pre-tension conditions (ie internal circumference) for microvascular studies is best defined as the size when the vessel is fully relaxed and under a transmural pressure of 100 mmHg. Therefore the aim of the normalization procedure is to determine the internal circumference at which the vessel would be relaxed and under a transmural pressure of 100 mmHg. This index is denoted as IC100 and is calculated for each vessel mounted on the wire myograph.
Data Analysis
For most experiments the degree of muscle contraction can be logged into the LabChart software 'Data Pad'. These values can then be further analyzed to produce a dose response curve. Suitable software for this analysis includes:
- GraphPad Prism software: Available for Windows and Macintosh. The results in the LabChart Data Pad can be exported to GraphPad Prism software which is then used for further analysis and to prepare Dose Response graphs (including Schild plots).
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 infromation, visit the Good Laboratory Practice application page or contact your nearest ADInstruments representative.
Related Areas fo Interest:
Radnoti Tissue/Organ Bath Principles Technique Note: Information about various techniques and principles related to isolated tissue/organ research applications.
Glassware Maintenance and Post-Experimental Cleaning Technique Note: Information about maintaining and cleaning glassware and other components manufactured by Radnoti Technology Inc. |
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| PowerLab (MacLab) citations: |
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| ncreased NADPH oxidase activity, gp91phox expression, and endothelium-dependent vasorelaxation during neointima formation in rabbits. |
| T.M. Paravicini, L.M. Gulluyan, G.J. Dusting, G.R. Drummond, Circulation Research, 91, 54-61, 2002 |
| Carotid artery rings from rabbits were suspended between 2 stainless steel wire hooks, one connected to an isometric force transducer ( FT-03 , Grass Instruments) and the other to an adjustable support. Preparations were immersed in water-jacketed organ baths containing Krebs bicarbonate Buffer. Circumferential force was measured with a Powerlab running Chart software (version 3.6.3; AD Instruments). |
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| Mechanism of RhoA/Rho kinase activation in endothelin-1-induced contraction in rabbit basilar artery. |
| L. Miao, Y. Dia, J. Zhang, American Journal of Physiology: Heart and Circulatory Physiology, 283, H983-H989, 2002 |
| The basilar arteries were removed from the rabbit and cut into 2-mm rings in a dissecting chamber filled with modified Krebs-Henseleit bicarbonate solution and bubbled with 95% O2-5% CO2.......endothelial cells were removed by gently rubbing the rings with a steel hook. Rings were suspended at the resting tension of 400 mg ( Radnoti transducer, Radnoti G lass) between stainless steel hooks in 10 water-jacketted tissue baths ( Radnoti Glass) in modified Krebs-Henseleit biocarbonate buffer with 95% O2-5% CO2 at 37°C. ......... Isometric force transducers were connected to arterial rings, and contraction was recorded with an eight-channel MacLab 8E and stored on a Power Macintosh computer. |
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The material on this page is provided in good faith and believed accurate at the time of writing. No responsibility will be taken, or liability accepted, for damages arising from the use of information herein. Readers are urged to check with respective manufacturers the accuracy of all product related information.
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