Week 5 drugs

Question 1

Atropine blocks actions of ACh at ____________ receptors. This causes ________ of the iris.

Answer 1

Atropine blocks actions of ACh at muscarinic receptors. This causes mydriasis of the iris (dilates the iris through contraction of the iris dilator muscle)

Question 2

Prazosin is an ____-_______ ________ antagonist, administration of prazosin causes vaso_________.

Answer 2

Prazosin is an alpha1-adrenergic receptor antagonist. Since alpha1-AdR activation causes vasoconstriction, administration of prazosin causes vasodilation.

Question 3

_________________ inhibitors increase ACh levels at target organs. Administration should cause cholinergic effects such as miosis, improve neuromuscular transmission in myasthenia, but could also cause neuromuscular weakness via _____ _________.

Answer 3

Acetylcholinesterase inhibitors increase ACh levels at target organs. Administration should cause cholinergic effects such as miosis, improve neuromuscular transmission in myasthenia, but could also cause neuromuscular weakness via nAChR desensitization.

Question 4

Muscarinic agonists mimic _____________ stimulation.

Answer 4

Muscarinic agonists mimic parasympathetic stimulation.

Question 5

Why do non-selective cholinergic agonists such as Ach have limited use?

Answer 5

Because they affect the entire ANS and neuromuscular system.

Question 6

What drugs are used for glaucoma and cataract surgery?

Answer 6

Non-selective cholinergic agonists such as Ach are used topically on the eye.

Muscarinic agonists lead to miosis (pupil constriction), contraction of the ciliary muscle (increases lens curvature) and decrease intraocular pressure.

Question 7

Edrophonium and Pyridostigmine are examples of drugs that inhibit _____________ and are used in the diagnosis and treatment of _________ _________.

Answer 7

Edrophonium and Pyridostigmine are examples of drugs that inhibit acetylcholinesterase and are used in the diagnosis and treatment of myasthenia gravis.

Question 8

What is myasthenia gravis?

Answer 8

Autoimmune disorder

Immune system produces antibodies that bind to and destroy nAChRs, making neurotransmission less effective.

Question 9

How does tetanus toxin work?
It binds to ______ _________ that blocks the release of _________ __________. These normally stop excitatory muscles from releasing ___________.

Answer 9

It binds to inhibitory neurons (Renshaw cells) that blocks the release of inhibitory neurotransmitters. These normally stop excitatory muscles from releasing ACh.

Question 10

Botulinum toxin works by blocking the release of ______

Answer 10

acetylcholine.