Pharmacology practical (effect of cholinergic drugs on isolated rabbit jejunum drug and drug response relationship)

1. Pharmacology practical
( Effect of Cholinergic drugs on isolated rabbit
jejunum drug & Drug response relationship )
By : Osama Al-Zahrani
@OSAMA_Z96

2. Objective :
- To show the effect of the cholinergic agonists.
- To show the effect of the cholinergic antagonists.
- To show the physiological antagonism phenomenon.
Materials :
- Organ bath simulated software (Strathclyde).
- Computer facilities.

3. Why did we take the jejunum exactly to do this experiment on it ?
Because the jejunum is containing all of the receptor .
Finkelman was the first scientist who do this experiment.
We need to keep the jejunum alive, by :
- Blood : Physiological salt solution.(Tyrode for jejunum).
- Oxygen
- Temperature : 37 C
To do the experiment we must have Organ bath .

4. Organ bath
The organ bath is consisting from :
1- Thermoregulatory device.
2- Water jacket.
3- Aeration tube.
4- Aspirator.
5- Glass coil.
Recording system :
1- Recorder : record the mechanical information.
2- Transducer (Isometric & Isotonic ) : Transform the mechanical information to
electrical information , to read it on the computer

5. Organ bath
Thermoregulatory device
Water jacket
Glass coil
Aeration tube
Aspirator

6. Recorder

7. Dose cycle
Steps of Dose cycle :
Normal > After 30s > add the drug to contraction > then wash
And repeat the previous steps.
Hint : we must keep the dose cycle fixed to get correct result.

8. Organ bath simulation application
How to use the application (Organ bath simulation) in computer ?
1- Open the application
2- You well see the app. Opened on “Chart” already.
3- Click on “New experiment” icon, then select Rabbit Jejunum.
4- Set the frequency on 2Hz
5- Click on “agonists” icon.
6- Set the drug, for example : Acetylcholine.
7- Set the “Stock soln” on : 1E-8M
8- Set the “volume” on 0.10
9- Click on “Record” to start the experiment.

9. After you started record wait 10s and when the line reached the
normal state click on “Add to Organ Bath” icon and wait until the
line reached its maximum state, and the click on “Click Drug from
Res.” icon (Wash) , and repeat these steps so on , but with
gradually change in “Stock soln” value with every dose..
Organ bath simulation application

10. Agonist drug (Acetylcholine)
Super maximumMaximum
Sub maximum
Dose 4Dose 3Dose 2Dose 1
Normal
Trace

11. Antagonist drug (Atropine)
Sub maximum
Dose 1
Dose 2
Dose 3
Dose 4
High dose
Atropine