Week 7 Practical Organ Bath Simulation

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PHR 582

Bioevaluation & Drug Screening Week 7 Practical

Organ Bath Simulation ____________________________________________________

Introduction: Simulation is defined as "the imitation of a real thing or process". It is applied in many fields including technology, engineering, training, learning & education.

In the current practical session, a computer software will be used to simulate previously studied pharmacological organ bath experiments.

Steps: 1. The following free link belongs to the "Strathclyde Institute of

Pharmacy and Biomedical Sciences". Click on this link; a variety of Pharmacology simulations programs will appear.

http://spider.science.strath.ac.uk/sipbs/software_sims.htm

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2. Download the installation file for "Virtual Organ Bath" and run setup by following stepwise instructions.

3. Open the Organ Bath Simulation program and examine the following: a. Tissue type (click on: new experiment) b. Agonists and antagonists (different drugs are available with

different stock concentrations). N.B. the volume added should not exceed 1 ml, the organ bath volume is 10 ml and the reservoir volume is 1000 ml.

c. Chart x-axis, which corresponds to the time. d. Chart y-axis, which corresponds to the force of contraction in gms.

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4. Select the guinea pig ileum as tissue type and histamine as agonist, then click on "Experimental Setup" to view a diagram for the whole system.

5. Return to "Chart" then click on "Record" to start the experiment.

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6. Select the volume of histamine to be added to the organ bath and the stock solution concentration so that the final organ bath concentration is 10-7 M, then click on "Add to Organ Bath"; leave histamine for 15 seconds, then click on "Flush Reservoir to Bath" in order to wash out histamine.

7. Add increasing doses of histamine using the previous procedure, leaving 30 seconds between successive doses until reaching the maximal response.

8. Click on "Stop" and measure the height of contraction (in gms) for each dose by scrolling the cursor shown below and simply recording the corresponding value.

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9. Construct a log-dose response curve for histamine using a semi-log paper as previously done (the x-axis corresponds to log dose volume and the y-axis corresponds to force of contraction in gms).

Dose (ml) Dose X .. Response (gms)