Reversal action of Acetylcholine on blood pressure in dog(Experimental Pharmacology -Virtual lab)

1. Reversal action of Ach on
Blood prerssure
By Dr. Sameh AM Abdelghany

2.  Chemical transmitters in PSNS
Acetylcholine(Ach):
 Synthesis and storage:
• Choline + Acetyl CoA → Acetylcholine + CoA

3.  Sites of release in ANS:
1. All autonomic ganglia.
2. All postganglionic parasympathetic fibers.
3. Postganganglionic sympathathetic fibers to sweat
glands.
4. Suprarenal medulla.
 Fate:
• by cholinesterase (ChE) enzyme

4.  Cholinergic receptors
Muscarnic receptors Nicotinic receptors
• Site - Effector organs supplied by
parasympathetic
- Sweat glands , Blood vessels
- CNS(Brain only)
- Autnominc ganglia (Nn)
- Adrenal medulla (Nn)
- Motor end plate(Nm)
- CNS spinal cord mainly (Nn)
• Subtypes M1, M2, M3, m4,m5 Nn , Nm
• Blockers Atropine - Ganglion blockers
- Neuromuscular blockers

5. Parasympathomimetics
Parasympathomimetics
Direct
Choline esters
e.g A.Ch
Alkaloids
e.g Pilocarp0ine
Indirect
Reversible
e.g Physostigmine
Irreversible
e.G Parathion

6.  Muscarinic actions
 Eye:-
 Miosis due to stimulation of M receptors in constrictor
pupillea ms
 Contract ciliary ms that leads to accommodation for near
vision
Secretions:
 Increase salivary , bronchial , gastric acid and sweat
secretions

7.  Respiratory system
Bronchospasm
Increase bronchial secretions

8. CVS:
Heart : ↓ all cardiac properties COP
Blood vessels: VD PR
Blood pressure: decrease BP(Hypotension)
due to:
i. Generalized VD of BV.
ii. ↓ COP

9.  Reversal action of AcH on blood pressure:
 Stimulation of M receptors in heart and blood vessels produce decrease in blood
pressure. After block of M eceptors by atropine, then nicotininc receptors stimulation
in sympathetic ganglia and adrenal medulla release endogenous catecholamines
which produce elevation in blood pressure

10. GIT:
Increase motility
Urinary tract:
Contract wall and relax sphincters

11.  Nicotinic effects
At Neuromuscular junctions
muscle twitches
Stimulation of all autonomic ganglia

17. THANK YOU