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Final Test: Dynamics II > Direct Acting Cholinergic Agonist > Flashcards

Direct Acting Cholinergic Agonist Flashcards

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1
Q

What are muscarinic receptor agonist?

A

parasympathomimetics

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2
Q

What are parasympathomimetics?

A

they mimic the parasympathetic response and bind directly to muscarinic receptors to elicit a second messenger-mediated response

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3
Q

What Is the primary use of parasympathomimetics?

A

primarily for diseases of the eye such as glacoma and accomadation estropia (crossed eyes) and diseases of the GI and urinary tract

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4
Q

What are choline esters?

A

they are a type of parasympathomimetic

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5
Q

Give an example of the choline esters?

A

acetylcholine HCl (michol)

bethanecol (urecholine)

carbachol (isopto carbachol, miostat)

methacholine (provaocholine)

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6
Q

What is acetylcholine mostly used for? And what is the formulation?

A

used in cataract extraction and surgical procedures of the anterior segment of the eye; ophthalmic solultion

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7
Q

What is carbachol used for? And what is the formulation?

A

used in cataract removal and anterior eye surgery and open angle glaucoma treatment; ophthalmic solution

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8
Q

What is bethanechol used for? And what is the formulation?

A

treating non-obstructive urinary retention following surgery, postpartum atony and for neurogenic atony

Other uses: post-op atony, megacolon, and gastrointestinal reflux

the administration will be oral and parenterally (SQ)

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9
Q

What is methacholine used for and what is the forumulation?

A

used for asthma diagnosis and bronchial airway hyperactivity diagnosis

administered as an inhalant with a physician present

but the use of methacholine for this has been discontinued

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10
Q

What is important to remember about methacholine?

A

the use of it has been discontinued

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11
Q

What is the mechanism of action for choline esters?

A

stimulation of muscarinic receptor subtypes at the ganglia and effector organs and the central nervous system (if it can get there)

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12
Q

What is important to recall about their molecule structure and how is this beneficial?

A

all four agents mentioned are permanetly charged quaternary amines and thy are poorly lipid soluble

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13
Q

Which drugs stimulate the nicotinic receptors?

A

ACh and carbachol

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14
Q

Which of the choline esters are less susceptible to the acetylcholinesterase and why?

A

carbachol and bethanecol are less susceptible to acetylcholinesterase because of the amine grup

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15
Q

Where are choline esters cleared?

A

in the kidney

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16
Q

Describe the molecualar structure of acetylcholine?

A

a quaternary amine (surrounded by four carbons–Ch2- a ester-CH3)

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17
Q

Describe the molecular structure of carbachol?

A

same a ACh except NH3

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18
Q

Describe the molecular structure of methacholine?

A

same as ACh except a methyl group attached to the CH group between quanternary amine

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19
Q

Describe the molecular sturce of bethanechol?

A

same as acetylcholine with both modifications of carbachol and methacholine

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20
Q

What is the cholinesterase susceptibility of acetylcholine chloride ?

A

very susceptible, the most out of all choline esters

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21
Q

What is the cholinesterase susceptibility of methacholine chloride?

A

low susceptibility but the second highest out of the group

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22
Q

What is the cholinesterase susceptibility of carbachol chloride?

A

negliable because of the NH2 group

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23
Q

What is the cholinesterase susceptibility of bethanecol chloride?

A

negligible because of the NH2 grup

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24
Q

What is the muscarinic action of acetylcholine chloride?

A

high muscarinic action (+++)

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25
What is the muscarinic action of methacholine chloride?
high muscarinic action (+++)
26
What is the mucarinic action of carbachol chloride?
lower muscarinic action, average (++)
27
What is the mucarinic action of bethanecol chloride?
low muscarinic action, average (++)
28
What is the nicotinic action of acetylcholine chloride?
its fairly high at (+++)
29
What is the nicotinic action of carbachol chloride?
its fairly high at (+++)
30
What is the nicotinic action of methachline chloride?
none because of the CH3 group
31
What is the nicotinic action of bethanecol chloride?
none because of CH3 group
32
What are the major physiological actions of choline esters with regards to the eye?
the opththamic preparation put in the eye contract the iris sphincter smooth muscle---\> cause constriction of pupil (miosis)---\>contract the ciliary muscle to cause accommodation for near sight the contraction of the sphincter pulls the iris away from the angle and contraction of the ciliary muscle stretch the tracecular meshwork to allow aqueous humor to flow out into the canal of schlemnm
33
What are the major physiological actions of choline esters with regards to glands?
stimulation of M3 receptors causes an increase in secretion of salivary, lachrymal, mucous and sweat glands
34
What are the major physiological actions of choline esters with regards to the cardiovasculature?
four effects: - lower heart rate because of M2 receptors which increase K+ conductance and leads to hyperpolarization of atrial cells - decrease conduction rate in the SA and AV nodes--by decreasing the slow inward Ca2+ current in atrial cells--hyperpolarization - decrease force of contraction - no direct cholinergic innervation of blood cells- there are muscarinic receptors on endothelial cells of vesses endothelial M3 receptors action---\> vasodialtion and relaxation as a result of stimulation of NO synthesis in endothelia cells---\> NO diffuses into smooth muscle cells and activates production of cGMP---\> cGMP activates PKG which increases K+ efflux from smooth muscle cells cause hyperpolarization and preventing Ca2+ influx--resulting in smooth cell relaxation
35
What are the major physiological actions of choline esters with regards to the GI tract?
all compounds produce an increase in GI tone, secretory activity and motility; GI contraction is due to depolarization of the muscle and an increase in Ca2+ influx
36
What are major physiological action of choline esters with regards to the urinary tract?
agonist contract he detrosor muscle, which rings the bladder, and relaxes trigone and sphincter muscles with allow voiding; sphincter relaxation is NO and cGMP mediated
37
What are the side effects of bethanecol?
well bethanecol is the only one that is administered systemically; the others are administered locally, mainly in the eye, and the systemic side effects are generally not a problem
38
How is bethanecol administered and how is this different thant other choline esters?
its give systemically
39
What are the side effects of inhalation of choline esters?
wheezing difficulty breathing headache itching throat irritation
40
What is the side effects of ophthalmic application of choline esters?
blurred vision eye pain irritation headache
41
What are the side effects of systemic application of choline esters?
bronchoconstriction: wheezing shortness of breath G.I.- belching diarrhea and urge to urinate blurred vision
42
When are patients contraindicated with the inhaled form of choline esters ?
patients with apparent asthma wheezing hayfever coronary insufficiency and hyperthyroidism
43
What drugs are contraindicated with the ophthalmic form of choline esters ?
belladona alkaloids (muscarinic antagonist) cycolpentolate
44
What conditions are contraindicated with the systemic form of choline esters?
asthma bradycardia CAD occlusions ulcers GI obstructions lesions recent surgery requiring atony
45
What are natural alkaloids? Give examples.
muscarine pilocarpine oxotremorpine
46
What is pilocarpine/ where is it found?
in the leaves of Pilocarpus plants in South America
47
What is muscarine where is it found?
in a variety of mushrooms- Amanita muscaria and species of Clitocybe and Inocybe
48
What is arecoline/ where is it found?
arecoline is found in betal nuts (Areca catecha) from the East Indies
49
How is pilocarpine administered and what is important about it?
pilocarpine is the the only alkaloid agent that is give therapeutically; Uses: found in ophthalmic solution for open and closed angle glaucoma secondary glaucoma induction of miosis for surger
50
What does pilocarpine do?
its the drug of choice for emergency lowering of intraocular pressure IOP regardless of the cause extremely effective in opening the trabecular meshwork around Schlemm's canal---increased drainage and immediate drope in IOP is observed---occurs within a few minutes and last 4 to 8 hours.
51
How does the body rid itself of pilocarpine?
excretion of the amines is via the kidney
52
What is the mechanism of action for natural alkaloids?
they have a similar mechanism of action as choline esters
53
What are the physiological actions of natural alkaloids?
they are essentially the same as the choline esters in the GI tract, eyes, glands, and SM
54
What are the cardiovascular effects of natural alkaloids?
it depends on the alkaloid: - muscarine has similar effects as choline esters - pilocarpine when given IV create hypertension in the long run---\>activates the sympathetic NS via stimulation of M1 receptors in the ganglia---\>sympathetic post-ganglionic neurons would be depolarized and release NE onto the vessels
55
What are the side effects and drug interactions when natural alkaloids are give by opthalmic route?
side effects and drug interactions from opthalmic use are the same as those for choline esters
56
What are the side effects of high levels of muscarine? How can this happen?
high levels of muscarine (known as mycetism or mushroom poisoning) produce SLUD: Salivation Lacrimation Urination Defecation As well as: hallucination (why some people eat!), bronchospasm, bradycardia, and hypotension. Atropine reverses effect.
57
What will reverse the effects of high levels of muscarine?
Atropine reverses effect
58
What can lower levels of muscarine still cause?
irritability and restlessness, ataxia, hallucinations and delirium; no atropine needed--support
59
What are some nicotinic receptor agents?
1) nicotine 2) lobeline 3) dimethylphenylpiperzinium
60
What is lobeline?
a plant derivative; lower potency than nicotine; with similar spectrum of action
61
What is dimethylphenylpiperazinium?
a potent synthetic agent; little CNS acess; research tool for selective ganglionic nicotinic receptor stimulation
62
What is nicotine?
primary stimulant and addictive substance in tobacco
63
What is the actions of nicotine?
addictive and stimulant properties occur in the CNS; substantial autonomic effects occur via stimulation of nicotinic receptors found in all autonomic ganglia
64
What is nicotine used for?
used therapeutically to facilitate the cessation of smoking by reducing withdrawals symptoms
65
What are the products that contain nicotine? Hint about 8 products.
1) nicotine gum (nicorette) 2) transdermal patches (Habitrol RX, NicodremCQ, Nicotrol, and Prostep) 3) lozanges (Commit) 4) oral inhaler (Nicotrol inhaler RX) 5) nasal spray (Nicrotol NS RX)
66
What are some important structural properties of nicotine and lobeline and why is this important?
nicotine and lobeline are tertiary amines - both are well absorbed from the lung (as a particulate), the buccal mucosa, and the skin - not well absorbed from the stomach but more so in the intestine
67
Where are nicotine agonist metabolized?
first the liver
68
Where is nicotine removed from the body?
excretion is renal; excreted in the milk of lactating women
69
What important concept is needed to know about nicotinic blockade?
1) first of course, the nicotinic agonist stimulated the nicotinic receptor causing it to open and allow the flow of Na+ into the postganglionic neuron 2) once the cell is depolarized it must repolarize to fire again 3) failure to repolarize, due to continued presence of the agonist leaves the cell inhibited 4) stimulation is transient; blockade is more persistent; thus initially nicotine is an agonist but in the end it becomes an antagonist
70
What are the physiological actions of nicotinic agonist such as nicotine and lobeline?
nicotine and lobeline stimulates and inhibits the autonomic ganglia both the SNS and the PSNS 1) activation of the SNS results in an increase in catecholamine release which stimulates the heart and constricts the vasculature 2)
71
What are the autonomic mediated side effects of nicotinic agonist ?
tachycardia andh hypertension
72
What happens during acute nicotinic poisoning in the GI, gland, cardiac, CNS, and skeletal muscle?
GI-nausea and vomitting glands-incred salivation and sweating cardiac- hypertension and cardia arrhythmias CNS-stimulation results in convulsions skeletal muscle-depolarization block which can paralyze the respiratory muscle
73
What are the contraindications of nicotinic agonist?
1) non-smokers- hypersensitivity to nicotine 2) pregnancy 3) severe angina pectoris 4) life threatening arrhythmias 5) patients who have hypertension: the benefit of nicotine replacement must outweigh the risk of continued cardiovascular insult
74
What are effects of nicotinic agonist in the eye and what condition is treated?
contraction- ciliary muscle and sphincter muscle of iris treats glacoma
75
What are the effects of nicotinic agonist in the GI tract and what condition is treated?
increases peristaltic movement and sphincter relaxation treats-adynamic ileus
76
What are the effects of nicotinic agonist in the urinary bladder and what condition is treated?
increases the contraction of detrusor muscle, sphincter relaxation treats urinary retension
77
What are the effects of nicotinic agonist in the vascular smooth muscle and what condition is treated?
dilation (minor effects)
78
What are the effects of nicotinic agonist in the bronchial smooth muscle and what condition is treated?
bronochoconstriction
79
What are the effects of nicotinic agonist on the body glands and what condition is treated?
secretion
80
What are effects of nicotinic agonist in the heart and what condition is treated?
1
81
How is acute nicotinic posioning treated?
with gastic lavage and activated charcoal

Final Test: Dynamics II (11 decks)

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