Cholinergics

Question 1

M3 receptor parasympathetic effects

Answer 1

contraction in eye (decrease IOP), urinary contraction (increase micturition), contraction of the gut (increase motility), contraction of lung (bronchoconstriction)

Question 2

M1 receptor effects

Answer 2

parasympathetic stimulation of mucosal glands (increase secretion)

Question 3

M3 sympathetic effects

Answer 3

increase sweat gland secretion

Question 4

M2 receptor effects

Answer 4

(parasympathetic) ↓ contraction & ↓ conduction of heart (↓ bp, bradycardia)

Question 5

M3 receptor other effects

Answer 5

vascular endoyhelium: ↓ bp, Reflex tachycardia (no innervation)

Question 6

Direct-Acting Cholinomimetic: Mechanisms of Action and Pharmacology

Answer 6

Activate muscarinic receptors
Affect all muscarinic receptor subtypes
Mainly evoke parasympathomimetic effects
Mild or no desensitization

Question 7

Bethanechol

Answer 7

Choline Ester (charged), not used to treat glaucoma (Charged molecules like bethanechol unable to adequately penetrate to the eye ciliary muscle)

Question 8

Pilocarpine

Answer 8

Alkaloid (uncharged, lipophilic), used to treat glaucoma

Question 9

Direct-Acting Cholinomimetic drugs

Answer 9

Bethanechol & Pilocarpine

Question 10

Direct-Acting Cholinomimetic drug negative effects

Answer 10

Parasympathetic effects:
Dizziness, headaches, bronchospasms, hypotension and reflex tachycardia, secretion, lacrimation, miosis, abdominal cramps, nausea, vomiting, diarrhea, urinary urgency, sweating

Question 11

Direct-Acting Cholinomimetic drug Precautions/Contraindications

Answer 11

Asthma, COPD, peptic ulcer, hypotension

Question 12

Direct-Acting Nicotinic Agonists

Answer 12

nicotine (an alkaloid)

Question 13

Can Nicotinic Acetylcholine Receptors become desensitized?

Answer 13

yes; with a prolonged agonist

Question 14

Direct-Acting Nicotinic Agonists stimulate

Answer 14

CNS, all peripheral ganglia and skeletal muscle (NMJ)

Question 15

Major clinical use of Direct-Acting Nicotinic Agonists

Answer 15

Smoking cessation

Question 16

Antimuscarinics: Mechanisms of Action and Pharmacology

Answer 16

Inhibit muscarinic receptors
Drugs available clinically generally act on all receptor subtypes*
Evoke parasympatholytic effects

Question 17

No innervation of muscarinic receptors in vasculature (except coronary arteries). Only effected by

Answer 17

‘circulating’ muscarinic agents. No agonist (ACh) –>No effect of antagonist. Antagonist effect only seen with ‘circulating’ muscarinic agents

Question 18

Quaternary amines such as __________, have poor absorption

Answer 18

Ipratropium (which treats asthma)

Question 19

Clinical Use of Antimuscarinics for Asthma

Answer 19

Atropine (3o)(no longer used), Ipratropium (4o) (inhaled)

Tiotropium (4o) (inhaled) (Bronchospasm in Chronic obstructive pulmonary disease (COPD), and asthma)

Question 20

ACh activates neuronal _________ as negative feedback control of ACh release

Answer 20

M2 receptor

Question 21

Ipratropium increases

Answer 21

ACh release from nerve

Question 22

Tiotropium blocks

Answer 22

M3 but not M2 receptors.

Question 23

A low dose atropine __________, but a higher dose _________.

Answer 23

increases ACh release(decreases HR); decreases ACh release (increase HR)

Question 24

Toxic effects of muscarinic antagonists

Answer 24

Blurred vision, photosensitivity; Agitation, hallucinations,
delirium, coma; Tachycardia, angina; Dry mouth, nasal
congestion, hot/flush skin, hyperthermia; Dysuria, retention; Nausea, distention, cramps, constipation
“Dry as a bone, blind as a bat, red as a beet, mad as a hatter, and hot as a hare.”

Question 25

Why are MUSCARINIC ANTAGONISTS CONTRAINDICATED FOR OPEN-ANGLE GLAUCOMA?

Answer 25

Atropine prevents activation of M3 | decreases humor outflow → increases IOP

Question 26

General Classes of Cholinesterase Inhibitors

Answer 26

reversible-4o Alcohols & Carbamates; irreversable-organophosphates

Question 27

Edrophonium

Answer 27

a 4o Alcohol; reversible Cholinesterase Inhibitor that binds to choline subsite and H+ bond to acyl pocket

Question 28

Physostigmine

Answer 28

a Carbamate; reversible Cholinesterase Inhibitor that binds like ACh with covalent bond, decarbamoylation rate slower than deacetylation rate.

Question 29

Physiological effects of inhibiting cholinesterase

Answer 29

increase EEG and Alertness, Parasympathomimetic Bradycardia, Stimulation, Low dose: indirect decrease in BP; Higher dose: increased Symp drive, increased strength, Similar to direct acting cholinomimetics

Question 30

In Myasthenia Gravis, you can use _______ for an eye test– rapid short acting, prevents fatigue of eyelid muscle and use _______ as a treatment

Answer 30

Edrophonium; | Physostigmine

Question 31

toxic effects of cholinesterase inhibition

Answer 31

increase EEG and Alertness, Convulsions -->Coma; Parasympathomimetic effects on heart; depression; hypotension; blockade of skeletal muscle; Similar to direct acting cholinomimetics

Question 32

Myasthenia Crisis Vs. Cholinesterase Crisis

Answer 32

Myasthenia Gravis is limited to the NMJ

Question 33

AChE Inhibitors used to treat Muscarinic Inhibitor poisoning and

Answer 33

vice versa

Question 34

Reversible AChE inhibitor used to treat

Answer 34

AChE Inhibitor poisoning

Question 35

Direct-acting cholinomimetics

Answer 35

Bethanechol, Pilocarpine, Acetylcholine, Nicotine

Question 36

reversible indirect-acting cholinomimetics

Answer 36

Edrophonium, Physostigmine, Echothiophate

Question 37

muscarinic inhibitors

Answer 37

Atropine, Ipratropium, Tiotropium

Question 38

Tiotropium blocks proinflammatory action of ACh, but allows

Answer 38

ACh to inhibit ACh release