Reversal action of Acetylcholine on blood pressure in dog

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: All autonomic ganglia. All postganglionic parasympathetic fibers. Postganganglionic sympathathetic fibers to sweat glands. 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

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: Generalized VD of BV. ↓ 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

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