2. Pharmacology of the Peripheral Nervous System (PNS) Dr. Sabry Attia 2008

3. Diagram of the major components of the central and peripheral nervous systems and their functional relationships. Stimuli from the environment convey information to processing circuits within the brain and spinal cord, which in turn interpret their significance and send signals to peripheral effectors that move the body and adjust the workings of its internal organs.

4. The vertebrate nervous system Peripheral Nervous System (PNS) Efferent nerves Motor component Autonomic NS Somatic NS Afferent nerves Sensory component NervesReceptors Central Nervous System (CNS) BrainSpinal Cord

6. Efferent nerves of the peripheral nervous system

7. Some anatomic and neurotransmitter features of autonomic and somatic motor nerves

8. Drugs acting on somatic nervous system 1. Non-depolarizing muscle relaxants (competitive antagonist)

9. Drugs acting on somatic nervous system 2. Depolarizing muscle relaxants (agonists)

10. Brainstem

11. Drugs Acting on the Parasympathetic Nervous System

12. Acetylcholine: release, effects, and degradation

13. Pilocarpine Direct and indirect parasympathomimetics ACh is too rapidly hydrolyzed and inactivated by AChE to be of any therapeutic use; however, its action can be mimicked by other substances, namely direct or indirect parasympathomimetics.

14. Uses of parasympathomimetics 1.in postoperative atonia of the bowel or bladder (neostigmine). 2.in myasthenia gravis to reverse the neuromuscular blockade (neostigmine) 3.antidote in poisoning with parasympatholytic drugs (physostigmine) 4.in the treatment of glaucoma (pilocarpine) 5.Insecticides (parathion) 6.in alleviating symptoms of dementia in some subtypes of Alzheimer’s disease (Tacrine)

15. Parasympatholytics Parasympatholytics are substances acting antagonistically at the M cholinoceptor. Effects of parasympathetic stimulation and blockade Ach

16. Uses of Parasympatholytics (Atropine-like drugs) Atropine; is used to prevent cardiac arrest and as a preanesthetic medication to prevents a possible hypersecretion of bronchial mucus, which cannot be expectorated by coughing during anesthesia. Homatropine; is used as mydriatics (for diagnostic use). Benzatropine; is used in treatment of Parkinson’s disease. Pirenzepine; is used in treatment of gastric and duodenal ulcers. Ipratropium; is used in treatment of bronchial asthma, bradycardia and heart block. N-butylscopolamine; is used in treatment of biliary and renal colic. Scopolamine; is used in treatment of motion sickness. Therapy of severe atropine-like drugs intoxication includes the administration of the indirect parasympathomimetic as physostigmine

17. Drugs Acting on the Sympathetic Nervous System

19. Inactivation of noradrenaline 1. Reuptake 2. 3.

20. Drugs Acting on the Sympathetic Nervous System Direct-acting sympathomimetics 1.Adrenaline (epinephrine) 2.Noradrenaline (norepinephrine) 3.Isoproterenol 4.Phenylephrine 5.Clonidine 6.Dobutamine 7.Salbutamol Indirect-acting sympathomimetics 1.Facilitate noradrenaline release (amphetamine), 2.Block noradrenaline re-uptake (cocaine) α1, α2` β1, β2 --------` β1, β2 α1 -------- Presynaptic α2` ------- -------- β1 -------- β2

22. β1 β α, β β1, β2

23. β α, β β2