PPT

1. Parasympathomimetics
(Cholinomimetics/Cholinergic receptor agonists)

2. Synthesis
Storage
Release
Actions
Metabolism (termination
of action)
Parasympathetic Nervous System

4. Actions of Acetyl
Choline
Actions on deferent receptors (Muscarinic and
Nicotinic)
All autonomic ganglia and effector organs (Eye,
salivary glands, Lungs, GIT, Heart, Blood Vs, UB,
Pancreas, Male sex Organs, Sweat glands, CNS)

5. Features of cholinergic receptors
Location Function MOA Agonists Antagonists
Nn Autonomic
ganglia, adrenal
medulla
Transmission of
impulse through
ganglia
Ligand gated
channels
Nicotine,
diphenyl
piperazenium
Hexamethonium,
trimetaphan,
mecamylamine
Nm Neuromuscular
junction
Contraction of
skeletal Ms
Ligand gated
channels
Acetyl choline,
Succinyl choline,
nicotine
D-tubocurarine,
alfa bungarotoxin
M1 Autonomic
ganglia, cortex,
hippocampus
(CNS, Gastric
cells , sm ms)
Gastric acid
secretion, GI
motility, CNS
excitation
Ligand gated
channels
oxotremorine Pirenzipine,
telenzipine,
M2 SA node, AV
node, atrium,
ventricles;
rate of impulse
generation,
velocity,
conduction,
contraction
Ligand gated
channels
methacoline triptiramine
M3 Exocrine glands,
smooth muscles,
vasculature
Gastric acid
secretion, GI
motility, CNS
excitation
Ligand gated
channels
bethanecol darifenacin

6. • Eye (ciliary, circular,
Lacrimal glands)
• Salivary glands
• Lungs
• GIT
• Heart
• Blood vessels
• Liver n Kidney
• Urinary bladder
• Pancreas
• Male sex organs
• Sweat glands
• CNS
• Miosis
• Saliva secretion
• Bronchus-Con,
secretions
• Peristalsis
• HR,FC, CO
• Dilatation
• -----
• Urine out flow
• Pancreatic juice
• Erection
• Sweat secretion
• CNS facilitation
Organ Function/Effect
Receptor
M3
M3
M3
M3 , M1
M2
M3
----
M3
M3
M3
M3
M3,Nn, M1

7. Ach metabolism

9. Cholinomimetics

12. Cholinergic drugs
Direct action
 Choline Esters
Acetylcholine
Methacholine
Carbacol
Bethanecol
 Natural alkaloids
Pilocarpine
Muscarine
Nicotine
Arecoline
Indirect action
(Anti cholinesterases)
 Reversible
Neostigmine
Physostigmine
Pyredostigmine
Ambenonium
Edrophonium
 Irreversible
Organophoshates
Ecothiophate
Malathion
Sumithion
Carbamates
Carbaryl(SEVIN)
Propoxure(BAYGON)
Aldicarb(TEMIK)

13. Sites of Ach release
Sites of Ach release

14. Synthesis of ACh

15. Metabolism of Ach
Acetyl cholinesterase / True cholinesterase
Butyryl cholinesterase / Pseudo cholinesterase
Acetylcholine Choline + Acetylated Enzyme
Hydration
Acetate + Free Cholinesterase
Cholinesterase

16. Acetylcholine
Organ system effects Including Adverse Effects:
Eye:
Miosis
Cyclospasm

17. CVS:
Negative chronotropic, inotropic and dromotropic
Hypotension
Respiratory System:
Bronchospasm, Increased secretions

18. GIT:
Genitourinary System:
Ganglia:
NMJ:
Ach used as miotic – cataract surgery

19. Carbachol , Bethanechol
Used for:
Post operative paralytic ileus
Congenital megacolon
GERD
Atony of Urinary bladder

21. Pilocarpine
Glaucoma - ocusert
Sjogren’s syndrome
Irradiation of head and neck
- Cevimeline

22. Edrophonium
Physostigmine, Neostigmine
Organophosphates
Acetylcholine Choline + Acetylated Enzyme
Hydration
Acetate + Free Cholinesterase
Cholinesterase
Indirectly acting drugs

23. Indirectly acting drugs
Reversible anticholinesterases:
Clinical Uses:
Glaucoma
Post operative paralytic ileus
Atony of the bladder
Myasthenia gravis
Reversal of NM blockade
Atropine poisoning
Alzheimer’s

24. Myasthenia Gravis is characterized by ,
Easy fatigability and progressive weakness of the striated
muscle and with intermittent periods of exacerbation.
Ptosis
Diplopia
Difficulty in speaking, swallowing
Extremity weakness
• All the muscles – including respiratory muscles.

26. Edrophonium in Diagnosis
Myasthenia crisis Vs Cholininergic crisis
Immuno-precipitation assay
EMG recording
EDROPHONIUM TEST / TENSILON TEST
Antistriated muscle antibody
Thymoma identification – CT SCANNING

27. Adverse effects of cholinomimitics
Nicotinic :
Muscarinic :
Contraindications

28. Irreversible anticholinesterases:
• Organophosphates (not drugs)
Organophosphorus Compounds- Poisoning- Treatment:
• Remove soiled clothes
• Wash skin, eyes
• ABC
• Inj. Atropine till atropinization
• Inj.Pralidoxime (Oximes)
• Inj. Diazepam for convulsions

29. Thank you