Dose Response

Overview:

Dose response studies are conducted extensively both in research and education. Traditionally, tissue-organ baths are used for in vitro dose response experiments, used extensively to investigate the physiology and pharmacology of tissue preparations from various species (chick, toad, rabbit, rat, guinea-pig, etc.)








Tissues or organs have been isolated for these studies include:

  • Muscle (Smooth or Skeletal)
  • Arterial rings or strips
  • Uterine tissue or Vas deferens
  • Ileum
  • Colon
  • Atrial or Ventricle
  • Diaphragm

Method:

Typically, these experiments are performed in a temperature controlled environment and perfused with an oxygenated physiological solution, which allows the study of evoked tissue responses to:

  • Pharmacological drug/agents (Dose Response studies)
  • Electrical stimulation
  • Both pharmacological and electrical stimulation


The recorded responses or biological activity usually are the contraction/relaxation of muscle in the tissue:

  • Force (isometric)
  • Displacement (isotonic)


Tissue Preparation

In addition, the tissue placement may vary depending on the tissue type such as:

  • Ring/Vessel Preparation
  • Strip Preparation


Electrical Stimulation

The electrical stimulus can either be constant current or constant voltage and can be used in:

  • Field Stimulation - The response evoked by electromagnetic field generating membrane depolarization and Ca2+ influx resulting in contraction and/or relaxation
  • Point Stimulation - The response evoked by local charge stimulus spreading from one excitable cell to another through the sarcolemma or adjacent cell membranes


Myography

In some isolated tissue-organ bath studies, a myograph (muscle writer) is used. A myograph is a device used for determining and recording the intensity (force), velocity, etc. generated at the different stages of a contracting muscle. They usually have transducers that convert force into an electrical output that can be displayed on an oscilloscope or a computer monitor.  Typical myographs include:

  • Wire myograph
  • Muscle strip myograph


Related Areas of Interest

  • Radnoti Tissue/Organ Bath Principles Technique Note: Information about various techniques and principles related to isolated tissue/organ research applications. Download (95 KB)
  • Glassware Maintenance and Post-Experimental Cleaning Technique Note: Information about maintaining and cleaning glassware and other components manufactured by Radnoti Technology Inc. Download (65 KB)
  • MLT0015 Isotonic Transducer Calibration and Operation Technique Note: Information about adjusting preload, measuring units of force and measuring units of displacement. Download (119 KB)

 

Software:

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.


 

For most experiments the degree of muscle contraction can be logged into the LabChart software 'Data Pad'. The results in the LabChart Data Pad can be exported to GraphPad Prism (Windows and Macintosh) software which is then used for further analysis and to prepare Dose Response graphs (including Schild plots).

Dose Response Module (Windows)
The MLS390/7 Dose Response Module provides easy analysis of dose response type data (response to stimulation by chemical, electrical or physical agonists) recorded in LabChart from various studies including:

  • Muscle contraction
  • Enzyme activity
  • Hormone secretion
  • Heart rate
  • Blood pressure
  • Membrane potential

This module provides:

  • Real-time or offline analysis
  • Automated or manual modes of analysis
  • Fast analysis of raw data to dose response parameters
    • Fast comment detection and conversion to dose response markers
    • Easy options for calculating different response parameters
    • Instant single or multiple dose response curves (Hill-curves) generation
    • Instant calculation of EC50 and Hill slopes  
  • Export options to other software applications for further analysis
 


Peak Analysis Module (Windows)
The MLS380/7 Peak Analysis Module provides automatic detection and analysis of multiple, but not overlapping, signal peaks in acquired waveforms. It can be applied to a wide range of waveforms including recorded signals from:

  • Isolated tissue studies
  • Hemodynamic measurements
  • Amperometry
  • Cardiac physiology
  • Neurophysiology
  • Current measurements.


It provides:

  • Real-time or offline analysis
  • Fast parameter extraction and analysis from single or multiple peaks
  • Automatic peak detection of an entire channel or a selection within a channel
  • Detection of positive or negative peaks
  • Provides several analysis presets suitable for general and specific types of waveforms
    • Evoked Response, Population Spike, Synaptic, Action Potential and Cardiac Action Potential
  • Instant tabulation of extracted parameters that can be exported to other applications
    • Height, width, area of the peak and time to peak

DMT Normalization Module (Windows and Macintosh)
The MLS065/7 DMT Normalization Module is designed for use with PowerLab data acquisition units, LabChart software and DMT Wire Myographs, and calculates the optimal pretension conditions for microvascular or any small tubular tissue research.

It provides:

  • Allows real-time and offline data recording and analysis
    • Tension
    • Stimulation amplitude
    • Temperature
    • Flow
  • Easy method of determining optimal microvascular pretension when using DMT myographs

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:

Features of the ADInstruments Organ Bath Systems include:

  • Modular or compact organ baths
  • Hardware and software for both real-time and offline data extraction and analysis
  • Accurately record and display temperature and force
  • Designed with features to maintain a stable set temperature
  • Various bath sizes for different tissue types available

Compact Organ Baths

ADInstruments provides the following range of organ baths manufactured by PanLab and Radnoti.

Preconfigured Multiple (4, 8, or 16) Chamber Compact Organ Bath Systems

Preconfigured Multiple (4, 8, or 16) Chamber Modular Organ Bath Systems


Myographs

Preconfigured Wire Myograph Systems
These systems include PowerLab Data Acquisition Units (MLS250 LabChart Pro and Scope software)


DMT Muscle Strip Myograph w/Touch Screen

  • DMT820MS Muscle Strip Myograph w/Touch Screen
    • 4 acid-resistant stainless steel chambers
    • Suitable for muscle strips > 3 mm – 15 mm
    • Clamp supports or vertical hooks with suture wire
    • Built-in high-resolution force transducers
    • High precision micrometers and temperature control

Instruments and Accessories

Stimulator
A suitable stimulator unit is used for organ baths studies that require stimulation. Stimulation can also be provided via the analog outputs of the PowerLab data acquisition unit. 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.


Stimulating Electrodes
There are several combination tissue support rods/stimulating electrodes suitable for use in organ baths larger than 10 ml. A general guide for the use of these electrodes is as follows:
Tissue strips/spirals - Straight, zig-zag or coil electrodes
Small samples - Coil or flat electrodes
Blood vessel rings- L-type electrode or tri-shaped tissue support

Electrodes

  • 160152-11 Universal Holder with Straight Electrode
  • 160152-12 Universal Holder with Zig-Zag Electrode
  • 160152-13 Universal Holder with Coil Electrode
  • 160152-14 Universal Holder with L-Shaped Electrode
  • 160152-15 Universal Holder with Flat Electrode
  • MLA0301 Single Platinum Ring Stimulating Electrode
  • MLA0302 Double Ring Platinum Stimulating Electrode
  • MLA0303 Platinum Stimulating Electrode
  • MLA0304 Double Ring Stimulating Electrode With Rings
  • MLA0305 Stainless Steel, Single Ring Stimulating Electrode
  • MLA0306 Stainless Steel, Double Ring Stimulating Electrode
  • MLA0307 Stainless Steel Stimulating Electrode
  • MLA0308 Stainless Steel Double Ring Stimulating Electrode
  • MLA250 Stimulator Cable BNC to Alligator Clip
  • MLA270 Stimulator Cable BNC to Micro-Hooks
  • MLA0320 Animal Nerve Stimulating Electrode


Bridge Amplifiers
Most of the transducers that are used for isolated tissue studies require a suitable preamplifier (usually a bridge amplifier) before the signal can be accurately recorded by PowerLab data acquisition system. Suitable amplifier units available from ADInstruments include the:


Transducers
ADInstruments provide a great variety of transducers suitable for a range of organ bath studies.

Isometric force transducer for measuring small changes in force:


Isometric research-grade force transducers suitable for use where larger forces are expected:


Wide-range, semi-isometric strain-gauge transducers:


Isotonic transducers for measuring displacement against a constant force:

 

Increased NADPH oxidase activity, gp91phox expression, and endothelium-dependent vasorelaxation during neointima formation in rabbits
T M Paravicini; L M Gulluyan; G J Dusting and G R Drummond, Circulation Research, 54-61, 2002

Mechanism of RhoA/Rho kinase activation in endothelin-1-induced contraction in rabbit basilar artery
L Miao, Y Dia and J Zhang, American Journal of Physiology: Heart and Circulatory Physiology, H983-H989, 2002

Pharmacological techniques for the in vitro study of the vas deferens
T D Westfall and D P Westfall, Journal of Pharmacolological and Toxicological Methods, 109-122, 2001

Citations Database


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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