1. PRACTICAL PHARMACOLOGY-1 (Po701) Third Year FACULTY OF PHARMACY Department of Pharmacology & Toxicology CAIRO UNIVERSITY شعارالكلية منارة التعليم الصيدلي في مصر ومحيطها الإقليمي

4. Why Ach contracts the skeletal muscle? Why carbachol contracts the skeletal muscle? Why K + contracts the skeletal muscle?

5. Aim: Determining the following properties of an unknown drug which causes skeletal muscle contraction: 1.Its susceptibility to destruction by cholinesterase enzyme (CE). 2.Its site of action (acts on Nm receptors or directly on the muscle).

6. Unknown drug Susceptibility to CE enzyme Action on Nm receptors Cholinester (e.g. Ach) ++ Carbamate ester (e.g. carbachol) _+ Direct skeletal muscle stimulant (e.g. K + ) __

7. ☺ How to test for susceptibility of the drug to destruction by CE?

8. Using anti-cholinesterase drug: Incubate the muscle with PHYSOSTIGMINE (anti- cholinesterase) then add the drug: if it is hydrolysed by CEif it is not hydrolysed by CE PHYSOSTIGMINE will prevent its destruction  ↑ its amount at receptor site  potentiation of muscle response PHYSOSTIGMINE will not change muscle response

9. ☺ How to find out the site of action of the drug?

10. Block Nm receptors by TUBOCURARINE (neuromuscular blocker), then add the drug: if it acts on Nm receptors muscle response will ↓ if it doesn't act on Nm receptors muscle response will not change

11. In this experiment: The muscle’s response to the drug before & after adding the experimental tools (PHYSOSTIGMINR, & TUBOCURARINE) is observed. Q. Can we add the SM dose as a reference dose only once at the beginning of the experiment? Ans. No, because the sensitivity of the muscle may change during the experiment leading to changes in muscle response.

12. 0.2 U 0.4 U 0.8 U 0.2 U 0.2 AntiChEs ( Physostigmine ) 5 min. OFF + NO WASH after 0.2 NMB ( Tubocurarine ) 5 min. OFF + NO WASH after 1.Susceptibility to destruction by cholinesterase: Not susceptible 2.Site of action: Direct 1.Susceptibility to destruction by cholinesterase: Not susceptible 2.Site of action: Direct Unknown may be K+

13. 0.2 U 0.4 U 0.8 U 0.2 U 0.2 AntiChEs ( Physostigmine ) 5 min. 0.2 NMB ( Tubocurarine ) 5 min. OFF + NO WASH after 1.Susceptibility to destruction by cholinesterase: Not susceptible 2.Site of action: Stimulates muscular N m receptors 1.Susceptibility to destruction by cholinesterase: Not susceptible 2.Site of action: Stimulates muscular N m receptors Unknown may be Carbachol

14. 0.2 U 0.4 U 0.8 U 0.2 U 0.2 AntiChEs ( Physostigmine ) 5 min. 0.2 NMB ( Tubocurarine ) 5 min. OFF + NO WASH after 1.Susceptibility to destruction by cholinesterase: Susceptible 2.Site of action: Stimulates muscular N m receptors 1.Susceptibility to destruction by cholinesterase: Susceptible 2.Site of action: Stimulates muscular N m receptors Unknown may be ACh

15. AChCarbacholK+ After Physostigmine  No change After Tubocurarine  No change

19. 29112014

20. 29 11 2014 Type code Select Lab time

21. 29 11 2014

22. Type your name your ID Press Start

25. Press Add Dose

26. 25

27. Complete the D/R relationship for the given UNK. solution (3 graded doses only)

28. Effect of anticholinesterase “physostigmine ”: 1.Choose a submax. dose 2.Repeat addition of submax. dose after the D/R 3.Incubate rectus with “physostigmine” 4.Repeat addition of submax. on incubated rectus Physostigmine Tubocurarine Physostigmine

29. Effect of neuromuscular blocker “tubocurarine ” Repeat the previous steps but with “tubocurarine”

31. Press printer icon to print Write your conclusion in the printed chart