Conceptual briefing of cholinergic system

1. Cholinergic system
Dr. Anant Khot

3. Nicotinic action of Ach
Dale’s experiment in Spinal cat

4. Pilocarpine
• Leaves of Pilocarpus
microphyllus
• ↑ Secretions- Saliva, lacrimal
& others
• Xerostomia, glaucoma & to
counteract mydriasis used for
refraction testing
• To prevent/break adhesions
• S/E- Sweating m.c

6. Mycetism
• Muscarine type (Early mushroom poisoning)
• Inocybe & Clitocybe species
• Onset- 30-60 min of ingestion
• Salivation, lacrimation, N/V/D, headache, visual
disturbances, abdominal colic, bronchospasm,
bradycardia, hypotension & shock
• Rx: Inj.Atropine sulfate 1-2mg IM every 30 min

7. RNA Polymerase
II

10. CNS toxicity

11. Anticholinesterase agents
• Calabar bean-Dried ripe seed of Physostigma
venenosum
• Native tribes of West Africa- Ordeal poison in
trials for Witchcraft
• 1864- Jobst & Hesse- Obtained Physostigmine
• 1877 – Laqueur-in the treatment of glaucoma
• 1931-Neostigmine was introduced into
therapeutics

12. Classification
• Alcohols- Have quaternary ammonium group
• E.g: Edrophonium
• Carbamates & related compounds- T/Q gp
• E.g: Physostigmine, neostigmine, pyridostigmine
• Organophosphates
• E.g: Echothiophate

16. M.O.A

17. 2 step reaction

18. Edrophonium
• It is a quaternary amine, binds reversibly to the
active center of AChE
• Use: Ameliorative test for diagnosis of MG
• For Post-operative decurarisation

19. Alzheimer’s disease

21. ?

22. MG

25. Uses
• As miotic

26. • Myasthenia gravis
• Postoperative paralytic ileus/urinary retention
• Postoperative decurarization
• Cobra bite
• Belladonna poisoning
• Alzheimer’s disease
• Antihelminthic agent- Metrifonate
• For the treatment of head lice infestation

29. Management
• Decontamination
• Stabilization: ABCs
• IV fluids as an initial bolus of 20 mL/kg
• IV diazepam for convulsions
• Antidote: Atropine (adult dose is 1 to 3 mg IV
bolus, Then titrate according to persistence of
bronchorrhea by giving the double of the
previously used dose every 5 minutes until
atropinization is achieved)
Once the patient is stabilized, an infusion of
atropine should be started with
10% to 20% of the initial atropinization dose
per hour- held if anticholinergic effects occur

30. Cholinesterase reactivators
• Restore NM transmission only in case of OP
poisoning
• Pralidoxime(2-PAM) -1 to 2 g in 100 mL NS IV
over 20 minutes, then infusion of 500 mg/hr
• C/I –Carbamate poisoning
• Other drugs- Obidoxime, DAM

32. Anticholinergic drugs