Cholinergics agonists
Which mimic the action of neurotransmitter acetylcholine

cholinergic receptors

mascarinic receptor

M1-found in gastric glands

M2 cardiac cells

M3-found in smooth muscle, eyes,lungs,digestive tract, exocrine glands(sweat & Salivary)

Nicotinic receptor

NM is located in the neuromuscular junction -responsible fo muscle constriction

N2 or NN located in the autonomic central nervous system Adrenal medulla - involve in transmission of cholonergics

Subtypes of mascarinic receptor

M1 and M3 are preferantially couple to the Gq-pathway

M2 favor Gi-pathway

*Gq-when stimulated leads to increase in intracellular levels of calcium


*Increasing intracellular Ca²± content trigger processes such as : construction,secreatilion and nuerotransmission

Stimulation of Gi can lead to opening of K± which in turn causes :hypoporalisation and reduction heart rate

Direct acting-mimic the effect of acetylcholine by binding to the mascarinic or nicotinic receptor

ACETYLHOLINE -have non-specific cholinergic effect.

When admitted intravenously


Decrease cardiac output,heart rate and blood pressure activities Increases GI activity

It is available in opthalmological solutions used to produce meiosis during eye surgery

CARBAHOL-has longer duration of action as far as theraptic use


It is used to local to construct pupil during eye surgery


It also decrease intra-ocular pressure.

PILACARPINE


Act on smooth muscle of the eyes to construct the pupil.
Treat the glaucoma attack

BETHANOTHOL


stimulate urinary and gastro instestinal tracts


*Given oral and sabcutanous


Treat: urinary retention, gastrointestinal lack of mascular tone

Indirect acting agonists-increases availability of ach act cholonergic receptors.

ADROPHONIUM
Bind to acetylcholine and acetate receptors and has a very long duration of about 10-20mins

Treatment:
Used to diagnosis of myasthenia gravis -is a nueromascular disease caused by antibodies that blocks acetylcholine receptor which leads to muscle weakness

PHYSOSTIGMINE
stimulation both mascarinic and nicotinic receptor
Has a duration of about 30 2 hours
Historical was used for overdoses of anticholinergic drugs such as Atropine rervese toic

NEOSTIGMINE
has small pores structure,it does not absorb well in GI tract
Does not enter CNS


It is used in: symptoms of myasthenia gravis
: Stimulation of bladder and GI tract

PYRIDOSTIGMINE- treatment of myasthenia gravis

Irreversible
Are extremely toxic

ECHOTHIOPHATE
acetylcholinesterase inhibitor used to increase the of intra ocular fluid.


Used to treat chronic glaucoma

Adverse effect

Broichorrhea

Miosis/muscle weakness

Urination

Diarrhoea

Bradycardia

Emests

Tacrimation

Salvation/sweating