Pharm - Lecture 10 - Muscarinic Agonists

Front 1

What are two modes of action for parasympathomimetics?

Back 1

1) Muscarinic agonists
2) AChE antagonists

Front 2

How do parasympatholytics function?

Back 2

They interfere with parasympathetic transmission, i.e. muscarinic antagonists.

Front 3

Name four Choline Esters important for this class:

Back 3

1) Acetylcholine
2) Carbachol
3) Methacholine
4) Bethanechol

Front 4

Why does IV ACh produce hypotension in low doses, and hypertension in high doses?

Back 4

1) Low dose IV ACh activates AChRs present in the BVs (not normally active)
2) Really high doses of IV ACh activate NICOTINIC AChRs in the adrenal medulla, causing a huge pressor response.

Front 5

What are the major physiologic responses from Choline administration?

Back 5

Vasodilation- blood vessels have mAChR
Heart - low doses cause reflex tachycardia; very high doses can cause bradycardia
GI - Increase tone, motility, secretions
Lungs - bronchoconstriction
Pupil - cause miosis
Increase secretions from exocrine glands

Front 6

Why/how does ACh cause vasodilation? Are there any PANS nerves innervating the peripheral BVs?

Back 6

No PANS nerves innervate the peripheral BVs. Endothelial cells have AChRs, and when activated release vasodilating NO.

Front 7

What are a few therapeutic uses of Choline Esters?

Back 7

1) Post-op GI Stimulant (Bethanechol)
2) Cataract and Glaucoma Tx

Front 8

What are the two major classes of muscarinic agonists?

Back 8

1) Choline Esters (acetylcholine)
2) Alkaloid Agonists (muscarine)

Front 9

What are the thereapeutic uses of Pilocarpine?

Back 9

Miosis- treatment of glaucoma
Xerostomia - Increase salivation for treatment of dry mouth

Front 10

What would ophthalmic administration of an AChE inhibitor produce?

Back 10

Ophthalmic administration of an AChE inhibitor will produce miosis (exacerbates PANS input -> pupil constriction). May be used in the treatment of glaucoma.