ANS Flashcards
1
Q
Tonically active
A
There is continuous basal discharge along SNS and PNS nerves established by “pacemaker” neurons in the brainstem
2
Q
ANS that has postganglionic cholinergic fibers
A
PNS
3
Q
ANS that has postganglionic muscarinic receptors
A
PNS
4
Q
Postganglionic neurotransmitters of PNS
A
ACh
Vasoactive intestinal peptide (VIP)
Nitric oxide (NO)
5
Q
Postganglionic neurotransmitters of SNS
A
Epi and norepi
ATP
Neuropeptide Y (NPY)
6
Q
Target cell types for SNS
SNS specific (no PNS)
A
Sweat glands and piloerector muscles
Liver, adipose, and kidney
Vascular smooth muscle
Lack PNS innervation
7
Q
What target cells for both SNS and PNS
A
Smooth muscle
Cardiac muscle
Cardiac conducting tissue
Endocrine/exocrine glandular tissue
8
Q
Physiologic competition between SNS/PNS and heart
A
PNS innervate only nodes of the heart - stimulation activates metabotropic AChR and slows HR
SNS innervate nodal cells of the heart, ventricular myocytes, and peripheral vasculature
9
Q
Physiologic competition between SNS/PNS and lungs
A
PNS innervation activates metabotropic AChR’s that cause bronchoconstriction and mucous secretion
SNS activate metabotropic adrenergic receptors that induce bronchodilation
PNS - bronchoconstriction and secretions
SNS - bronchodilation
10
Q
Physiologic competition between SNS/PNS and the eyes
A
PNS innervation activates metabotropic AChR’s that cause pupillary constriction and allow for accommodation (parasympathetics innervate the iris dilator muscle. Pupils constrict because the iris dilator contracts)
SNS innervation activates metabotropic adreneric receptors that cause pupillary dilation and has no effect on accomodation (SNS innervates the radial muscle - when contracted, the pupil is dilated)
Accomodation refers to the contraction of the ciliary muscles attached to the lens, which allows the lens to become more rounded - better able to focus on near objects (PNS control)
11
Q
HR w/ and w/o PNS innervation
A
SA node w/ PNS drive - 60-100 bpm
SA node w/o PNS drive - 100-110 bpm (intrinsic automaticity of SA node)
12
Q
Thermoregulatory (eccrine) sweat glands
A
Activated by ACh released by sympathetic nerves (exception to rule that sympathetic nerves are adrenergic)
13
Q
ANS control of bladder function
A
Filling - SNS predominates (relaxation of detrusor m. and contraction of internal sphincter)
Micturition - PNS predominates (contraction of detrusor m. and relaxation of internal sphincter)
α1 - in internal sphincter
β 2 , adrenoreceptor in detrusor muscle L1–L3, lumbar segments
M, muscarinic cholinoreceptor in detrusor muscle and internal sphincter S2–S4, sacral segments
14
Q
Thoracolumbar outflow
A
15
Q
Craniosacral outflow
A
16
Q
MOA and target tissue of α 1 receptors
A
17
Q
MOA and target tissues of α 2 receptors
A
18
Q
MOA and target tissues of β 1 receptors
A
19
Q
MOA and target tissues of β 2 receptors
A
20
Q
MOA and target tissues of nicotinic receptors
A
21
Q
MOA and target tissues of muscarinic tissues
A
22
Q
Only type of agent that prevents accomodation of the eye?
A
PNS antagonist
23
Q
All preganglionic neurons release ______, and all postganglionic neurons have ______ receptors
A
All preganglionic neurons release ACh and all postganglionic neurons have nicotinic AChR’s
no matter where we are in the body, everywhere and always within the autonomic nervous system, the first synapse from preganglionic to postganglionic tissue uses the neurotransmitter acetylcholine and i tgoes to a nicotinic acetylcholine receptor.
24
Q
Does the PNS or SNS exit the spinal cord and form a trunk?
A
SNS forms a sympathetic trunk
PNS nerves stay separate
25
SNS innervation of adrenal medulla
Specialized sets of preganglionic SNS neurons do not synapse with a postganglionic neuron with a ganglion, but rather continue to the adrenal medulla where the medullary cells act as their ganglion.
The adrenal medullary cells have ACh receptors, just like a ganglionic neuron.
The cells of the adrenal medulla are neuroendocrine
26
Difference between epi/norepi and what receptors they bind
Epinephrine binds α1, α2, β1, and β2
**Epi has access to β2; norepi
doesn’t.**
β2 acts as sympathetic tone but also acts to check the norepi signal.
27
β2 receptor activation in vascular smooth muscle
Only activated by epinephrine - induces smooth muscle relaxation (all beta receptors raise cAMP in target tissues)
28
What causes constriction of smooth muscle arterioles?
Binding of norepinephrine onto alpha-1 receptors
29
β2 receptors in skeletal muscle only respond to what?
Circulating epinephrine (as opposed to direct innervation)
## Footnote
This is a delayed response relative to the sympathetic activation of alpha-1 receptors (vasoconstriction by binding of norepi) - **alpha-1 receptors are also activated by circulating epi**
30
What causes vasodilation in exercising muscle
Local metabolites and autoregulation
31
What is the response of skeletal muscle vasculature to sympathetic nerve stimulation?
Vasoconstriction
32
Rate and force of contraction of the heart
| ANS control
β1 are the primary receptors and stimulation causes increase in both.
However, the dominant repsonse is cholinergic - causing decrease in both
33
Predominant tone of all blood vessels
Sympathetic
34
Predominant tone of bronchial tree
Parasympathetic
35
Muscarinic vs. nicotinic receptors
36
What enzyme converts norepinephrine to epinephrine?
Phenylethanolamine-N-methyltransferase
37
Enzymes that metabolize norepinephrine and terminate its actions
Monoamine oxidase and catechol-O-methyltransferase
38
NE biosynthesis
| Diagram
39
Adrenergic receptors and their direct response
| Diagram
40
All adrenergic receptors are ______, and activate through ______
All adrenergic receptors are **metabotropic** and activate through **G proteins (Gi, Gs, Gq)**.
41
A) site 2
42
Atropine is a drug that is useful for dilating the pupil and it also paralyzes accommodation. These effects of atropine occur at which of the following sites on the diagram above (in question 1)?
D) Site 6
43
The flight or fight response is made possible by high levels of epinephrine circulating throughout the body, acting as a hormone, rather than a neurotransmitter. When acting at beta-2 receptors in the vasculature of skeletal muscle, what is the physiologic effect?
Vasodilation
44
Which enzyme is the rate-limiting step involved with synthesizing acetylcholine?
Choline acetyltransferase
45
M2 muscarinic receptors act via which second messenger pathways?
Decrease cAMP
46
ACh biosynthesis
47
Agonist and antagonist of nicotinic receptors
Agonist - ACh/Nicotine
Antagonist - Trimethaphan (Nn) only and curare (Nnmj) only
48
Agonist and antagonist of muscarinic recptors
Agonist - ACh and muscarine
Antagonist - atropine
49
Smooth muscle in vascular endothelium
| Constriction of vessel diagram
50
Smooth muscle in vascular endothelium
| Dilation of vessel diagram
51
Myocardial contractility
| Diagram - MOA of norepi
52
Eccrine sweat glands involved in thermoregulation are innervated by what nerve fiber types?
Cholinergic postganglionic sympathetic fibers
53
Rapid activation of the sympathetic nervous system as in response to a fight or flight event (a lion walking into your backyard) will stimulate all of the following except one. Which is the exception?
Dilation of arterioles in skeletal muscle
54
The function of which of the following organs or systems is dominated by the sympathetic nervous system?
Systemic blood vessels
55
The odd muscarinic receptors (M1, M3, M5) primarily impact which second messenger pathway component?
Activate phospholipase C
56
What enzyme is the rate-limiting step in norepinephrine biosynthesis?
Tyrosine beta hydroxylase
57
Stimulation of which adrenergic receptor is associated w/ increased heart rate and increased myocardial contractility?
Beta 1 receptor stimulation
58
Which of the following is the common link inside vascular smooth muscle cells that is (a) activated when norepinephrine stimulates alpha 1 receptors and is (b) inhibited after epinephrine stimulates beta 2 receptors?
Myosin light chain kinase
59
If you administer a drug that blocks the nicotinic receptors in the ganglia, what do you expect will happen to heart rate?
The HR will increase
60
Steps between norepi binding to an alpha-1 receptor in smooth muscle vasculature and physiologic response of vasoconstriction
1. Signal transduction through Gq
2. Activation of phospholipase C
3. Liberation of inositol triphosphate and diacylglycerol
4. Intracellular calcium levels rise
5. Calcium combines with calmodulin
6. Myosin light chain kinase is activated
7. Myosin becomes phosphorylated
8. Actin and myosin interact
61
List steps between epi binding to a beta-2 receptor in smooth muscle of the lung and the physiologic response of bronchodilation
1. Signal transduction through Gs
2. Activation of adenylyl cyclase
3. Formation of cAMP
4. Activation of protein kinase A
5. Phosphorylation of myosin light chain kinase
62
List the steps between norepi binding to a beta-1 receptor in heart and the physiologic response of tachycardia
1. Signal transduction through Gs
2. Activation of adenylyl cyclase
3. Formation of cAMP
4. Activation of protein kinase A
5. Increased intracellular calcium levels
63
Biochemical function of alpha receptors
**alpha-1 = phospholipase C activation**, resulting in an increase in intracellular calcium
**alpha-2 = inhibition of adenylyl cyclase**, resulting in decreased cAMP
64
Physiological effect of alpha-1 receptor agonistic binding
Contraction of smooth muscles of urinary tract (bladder/prostate)
Exocrine gland secretion
Neuronal excitation
65
Physiological effect of alpha-2 receptor agonistic binding
Inhibition of norepinephrine release
Decrease in secretion of aqueous humor
Decrease in insulin secretion
Platelet aggregation
CNS effects (sedation)
66
Physiological effect of beta-1 receptor agonistic binding
Increase in secretion of renin
Increase in HR, contractility, and conduction
67
Physiological effect of beta-2 receptor agonistic binding
Glycogenolysis
Relaxation of smooth muscles
Uptake of potassium in skeletal muscles
68
Physiological effect of beta-3 receptor agonistic binding
Lipolysis
Thermogenesis
Relax detrusor
69
What are the biochemical effects of agonistic binding to beta-1 receptors?
**Adenylyl cyclase activation** - resulting in increased levels of cAMP and protein kinase A activation
## Footnote
Increases HR and contractility
Also increases secretion of renin
70
What are the biochemical effects of agonistic binding to beta-2 receptors?
**Adenylyl cyclase activation** - resulting in increased levels of cAMP and protein kinase A activation
## Footnote
Beta-2 may also begin to couple go Gi in specific situations (i.e. HF)
71
What are the biochemical effects of agonistic binding to beta-3 receptors?
**Adenylyl cyclase activation** - resulting in increased levels of cAMP and protein kinase A activation
## Footnote
Results in lipolysis
72
Where are alpha-1 receptors usually found?
Smooth muscle
73
Main targets of NE and epi at low doese
NE - alpha receptors
Epi - beta receptors
74
What receptors are linked to Gq proteins?
**Alpha-1 receptors**
75
What receptors are linked to Gi proteins?
**Alpha-2 receptors** (and sometimes beta-2)
76
What adrenergic receptor class leads to cellular hyperpolarization upon agonistic binding?
**Alpha-2** = linked to Gi - decreases cAMP and promotes efflux of K+
| **Often autoreceptors**
77
What adrenergic receptor class leads to vasoconstriction upon agonistic binding
**Alpha-1 receptors** are linked to Gq proteins - which increase Ca2+ levels inside cells, leading to contraction of smooth muscle
| Also leads to **release of neurotransmitters** in neurons
78
Midodrine
**Alpha-1** agonist
Tx low BP in POTS
79
Phenylephrine
**Alpha-1 agonist**
Causes rebound congestion (**rhinitis medicamentosa**) if used incorrectly due to tissue damage from poor blood flow
## Footnote
Phenylephrine can also be used as a **vasopressor** in emergencies to raise BP
80
Agonistic binding of what adrenergic receptor causes mydriasis?
Agonistic binding of **alpha-1 receptors** causes **pupil dilation** by contracting the **radial muscle**
## Footnote
Alpha-1 increases phospholipase C activity which usually leads to contraction
81
Direct-acting presynaptic alpha-2 agonists
| List examples
Clonidine
Dexmedetomidine
Methyldopa
82
Clonidine
Acts on **alpha-2 autoreceptors**
Inhibits further NE relase
Used as a 3rd or 4th line Tx fo hypertension and also for ADHD
Causes profound sedation
83
Dexmedetomidine
Direct-acting presynaptic **alpha-2 agonist**
Often used during surgery or in ICU to provide **sedation w/o causing respiratory depression**
84
Methyldopa
Prodrug - converted by dopa decarboxylase and dopamine beta-hydroxylase to a false neurotransmitter - **alpha-methylnorepinephrine**, which is stored inside vesicles
When neurons depolarize it is released - alpha-methylNE displaces dopamine and NE, acting as an **agonist on alpha-2 presynaptic autoreceptors**
**Ultimately leads to less neurotransmitter release**
Used in OB to Tx pregnancy-induced hypertension (pre-eclampsia) becuase of its safety profile
## Footnote
Ezymatic conversion occurs in neurons
85
What drugs are used to reduce intraocular pressure by decreasing the production of aqueous humor and increasing its drainage?
Alpha-2 agonists:
**Brimonidine** or **apraclonidine**
86
Ephedrine
Indirect-acting sympathomimetic
Stimulates release of catecholamines from nerve terminals
Relatively resistant to MAO and COMT
## Footnote
Also pseudoephedrine
87
Tyramine
Indirect-acting sympathomimetic
Found in food
Stimulates release of pre-formed catecholamines
Normally degraded rapidly by MAO in gut - hypertensive crisis when MAO is compromised
88
What indirect-acting sympathomimetic inhibits norepinephrine reuptake transporters?
Cocaine bitch
89
What indirect-acting sympathomimetic causes reverse transport of norepi/dopamine out through the reuptake transporters?
Amphetamine/Methylphenidate
90
Phentolamine
**Non-selective alpha antagonist** (block both alpha-1 and 2)
Short-acting and reversible blocker (name is shorter than other non-selective alpha antagonist)
Administered IV
91
Phenoxybenzamine
Non-selective alpha antagonist
Long-acting and irreversible blocker
Administered orally
92
What drugs block the effects of epinephrine, and when would it be pertinent to do so?
Phentolamine and phenoxybenzamine are both **non-selective alpha antagonists**
They are used primarily to Tx Pt's w/ **pheochromocytoma** (adrenal tumor that releases excess catecholamines) - especially important during surgery - where manipulation of the tumor can release epi
Also used to Tx Pt's w/ **frostbite**: IV phentolamine vasodilates quickly to restore perfusion
93
Selective alpha-1 antagonists
Prazosin/doxazosin/terzosin - vasodilation (3rd/4th line antihypertensives due to side-effects)
Side-effects:
**First-dose syncope** (esp. Pt's that are dehydrates or sodium-deplete [diuretics], due to sudden venous pooling)
**Reflex tachycardia** due to baroreceptor activation as BP drops
**Miosis** - pupillary constriction
## Footnote
Tamsulosin/alfuzosin/sildosin - Tx BPH and have greater selectivity for alpha-1 receptors in prostate gland
93
Where are beta-1 receptors primarily found?
Heart and kidneys
93
Where are beta-2 receptors primarily found?
Lungs, blood vessels, and smooth muscles (i.e. the uterus)
94
95
Baroreceptors
Pressure-sensors in the carotids and aortic arch
Send signal to the ventrolateral medulla, nucleus of the solitary tract - activate the sympathetic nervous system to raise HR and BP
Selective alpha-1 antagonist can trigger reflex tachycardia (TPR decreases - increasing CO w/ increase in HR)
96
What happens to heart rate when phenylephrine is infused?
HR decreases
97
What is the mechanism of pseudoephedrine?
Promote release of preformed catecholamines
98
Which G protein do alpha-2 receptors couple to?
Alpha-2 receptors couple to Gi proteins
99
Give an example of a cardioselective antihypertensive
Metoprolol
100
Clonidine and methyldopa share some similarities in terms of actions at which of the following receptors?
Alpha 2
101
What drugs cause reflex tachycardia?
Drugs that induce vasodilation - alpha-1 antagonists and beta-2 agonists
102
When NE is administered after pre-Tx w/ atropine (prototypical muscarinic receptor antagonist) what is the response in HR?
Increase in HR caused by direct cardiac action
103
A possible effect of administering a beta-2 agonist to a patient is?
C. Skeletal muscle tremor
104
A possible effect of administering a beta-1 agonist to a patient is?
A. Direct stimulation of renin release
105
Pindolol
Partial beta-1 and 2 agonist (intrinsic sympathomimetic activity) - does not slow HR as much as a pure antagonist
106
Which of the following produces the traces shown in B?
A. Epi
B. Isoproterenol
C. Norepi
Epinephrine is associated with trace B
## Footnote
Norepinephrine is associated with trace A
Isoproterenol is associated with trace C
107
M1, M3, and M5 muscarinic receptors
Are linked to Gq proteins, which generally cause smooth muscle contraction
108
M2 and M4 muscarinic receptors
Linked to Gi proteins, which usually inhibit cells by hyperpolarizing them
109
Where are M1 receptors found?
In nerves
110
Where are M2 receptors found?
Primarily the heart
111
Where are M3 receptors found?
They are found in glands, smooth muscle of the lungs and bladder, blood vessels, and the eye
112
Where are M4 and M5 receptors found?
Mainly in the CNS
113
Ng (aka Nn) receptors
Nicotinic receptors found in nicotinic ganglia
Ng = nicotinic ganglia
Nn = nicotinic neuronal receptors
114
How do indirect-acting muscarinic agonists work?
By inhibiting **acetylcholinesterase** (**AChE**) - breaks down ACh
Allows more ACh to remain in synapse, increasing stimulation of both muscarinic and nicotinic receptors
115
Muscarinic agonist effects
Mnemonic: SLUD + Miosis
**S**alivation
**L**acrimation
**U**rination
**D**efecation
## Footnote
Other effects: **hypotension** (due to vasodilation), and **bronchoconstriction**
116
Three main classes of indirect-acting cholinergic agonists
1. **Alcohols** (i.e. edrophonium): Bind to AChE and are rapidly broken down by hydrolysis
2. **Carbamates** (i.e. pyridostigmine, physostigmine, neostigmine): Bind to AChE and are broken down more slowly than alcohols
3. **Organophosphates** (i.e. echothiophate, insecticides, nerve gases): Bind to AChE and hdryolyze very slowly or form covalent bonds with the enzyme
117
Pralidoxime
Used to treat organophosphate poisoning - to regenerate AChE - only works if Tx is given before aging occurs
| Aging - the formation of covalent bond to AChE
118
Muscarinic receptor antagonist
1. Red as a beet
2. Dry as a bone
3. Blind as a bat
4. Mad as a hatter
1. Block sweating - causes flushing
2. Reduced secretions (saliva/mucous) - dry mouth/skin
3. Impair visions by blocking accomodation (focusing close up)
4. In higher doses - confusion or delerium
119
Muscarinic antagonist used to treat bradycardia
Atropine
120
Muscarinic antagonist used to treat athma/COPD
Drugs like **ipratopium** and **tiotropium** *block* **M3** receptors in the lungs - bronchodilation and decreased mucus production
121
Muscarinic antagonist used to treat diarrhea/IBS
Drugs like dicyclomine - slow down GI motility and reduce cramping
122
Muscarinic antagonist used to treat overactive bladder
Drugs like oxybutynin - block contractions of the detrusor
123
Muscarinic antagonist used to treat motion sickness
The scopolamine patch - blocks ACh in the brain's vomiting center
124
What conditions do muscarinic antagonists worsen?
Cognitive decline in the elderly - esp. Alzheimer's or dementia
Hyperthermia - antimuscarinics prevent sweating
125
Muscarinic antagonists effects on the eyes
**Mydriasis** (pupil dilation due to relaxation of the iris sphincter (**tropicamide** dilates pupil)
**Dry eyes**
**Worsening of glaucoma** - they reduce aqeous humor outflow and can increase intraocular pressure (contraindicated in Pt's w/ **angle-closure glaucoma**)
**Cycloplegia** (loss of accomodation due to relaxation of the ciliary muscle which causes the lens to flatten)
126
Varenicline
Partial agonist/antagonist at nicotonic receptors - helping satisfy cravings while simultaneously blocking full effects of nicotine
127
Nicotinic Antagonists
**Neuromuscular junction blockers**: succinylcholine (depolarizing blocker)
Non-depolarizing blockers (**Curare derivatives**): atracurium, rocuronium, vecuronium
128
Succinylcholine
Initially activates nicotinic receptors (Nnmj) causing Na+ to influx, depolarizing the cell and resulting in muscle contraction (fasciculations). However, it stays bound to the receptor, preventing repolarization, which leads to prolonged muscle paralysis
Adverse effects: hyperkalemia and malignant hyperthermia (Tx with dantrolene - prevents Ca2+ from SR)
## Footnote
Short duration of action (~8 min.) and is metabolized by **plasma cholinesterase** (aka **butrylcholinesterase**)
129
Competitive antagonists at the Nnmj
Atracurium, rocuronium, and vecuronium are non-depolarizing Nnmr blockers
~25-120 min duration (depends on drug)
Indirect-acting muscarinic agonists can be administered to increase the level of ACh in the synapse
130
B. Neuromuscular end-plate
131
A. Increase bladder tone
132
B. M3
133
D. Both may increase GI motility
134
C. Increase GI motility
135
B. Increased cardiac rate
136
Physostigmine
137
A. Increased intraocular pressure
138
Receptor specificity of bethanecol
Muscarinic
## Footnote
Used for GI and urinary stimulation
139
Receptor specificity for carbachol
Muscarinic and nicotinic receptors
## Footnote
Used to induce miosis during ophthalmic surger
140
Receptor specificity for pilocarpine
Muscarinic receptors
## Footnote
Applied topically to the eye to Tx glaucoma (lowers intraocular pressure)
Also oral Tx for xerostomia (dry mouth)
Side effect: decrased night vision caused by miosis and difficulty focusing on distant objects (lens is accomodated for near vision)
141
Why don't choline esters distribute to the CNS?
They contain a quartenary ammonium derivative
142
Cevimeline
Muscarinic agonist to Tx dry mouth
143
What drug is used to Dx myasthenia gravis?
Edrophonium IV
144
Echothiophate
Applied topically to the eye to Tx glaucoma and accommodative estropia (binds to cholinesterase quasi-reversibly)
##Footnote
Miosis
Contracts ciliary muscle (improves focus through “spasm of accommodation”)
145
MOA of acetylcholinesterase hydrolyzing acetylcholine
146
MOA of acetylcholinesterase hydrolyzing neostigmine
147
What type of receptors are the nicotinic receptors found at the ganglia?
Ionotropic
148
Which of the following is a depolarizing nicotinic receptor blocker?
Succinylcholine
149
What is the site of action of vecuronium
Nicotinic receptors at the neuromuscular junction (Nnmj)
##Footnote
Competitive Zach antagonist
150
Which of the following is used as an antidote for organophosphate poisoning?
Praladoxime
151
MOA of scopolamine
152
MOA of bethanechol
Muscarinic receptor agonist
## Footnote
GI and urinary stimulation
153
MOA of atropine
Muscarinic receptor antagonist
## Footnote
Increase HR
154
MOA of neostigmine
Acetylcholinesterase inhibitor
155
Muscarinic receptor agonist effect on the eye
156
Muscarinic receptor antagonist effect on the eye
157
When is norepi used
To Tx warm shock: when BP is low and HR is high; mainly used clinically as a vasopressor
158
When is epi used
When BP is high and HR is low (cold shock); used for anaphylaxis to bronchodilate, increase HR, and vasoconstrict to counteract widespread vasodilatio; ACLS to stimulate heart; bronchospask
159
When is isoproterenol used
To increase myocardial contractility (i.e. decompennsated heart failure, cardiogenic shock)
160
Cycloplegia
Paralysis of accomodation due to relaxation of the ciliary muscle (cannot see up close, only far away)
## Footnote
Physiologic consequence of anti-muscarinics
161
Antimuscarinic effect on intraocular pressure (IOP)?
Increases IOP
162
-olol drug effects on the eye
Beta blockers decrease the production of aqueous humor
163
Why Dx myasthenia gravis w/ IV atropine and edrophonium
Atropine - antimuscarinic
Edrophonium - acetylcholinesterase inhibitor
| Blocking - SLUD syndrome with atropine
164
What is used IV to reverse muscle paralysis?
Neostigmine
165
What is the drug used for maintenance of myasthenia gravis?
Pyridostigmine
## Footnote
Cholinergic crisis is common during initial Tx - too much stimulation of Nnmj receptors does not allow for repolarization
166
What type of drug (class) is used to Tx urinary retention?
Muscarinic receptor agonist
167
Which of the following drugs is used to Tx open-angle glaucoma and has a side-effect profile of: difficulty with far vision and problems seeing in dim light.
A. Pilocarpine
B. Timolol
C. Apraclonidine
D. Epinephrine
E. Phenylephrine
A. Pilocarpine
| Pilocarpine is a muscarinic receptor agonist
## Footnote
Pilocarpine causes the ciliary muscle to contract, which increases tension on the scleral spur and opens the trabecular meshwork. This allows aqueous humor to drain from the eye, which decreases intraocular pressure while also decreasing one's ability for far vision.
168
What type of receptors control sweat glands and what are they innervated by?
The SNS innervates M3 receptors at sweat glands
169
When pupillary dilation but not cycloplegia is desired, the best drug to use would be a drug that has a similar MOA as which of the following?
A. Isoproteronol
B. Phenylephrine
C. Pilocarpine
D. Tropicamide
B. Phenylephrine
## Footnote
Alpha-1 agonist will produce mydriasis without cycloplegia. Cholinergic antagonist drugs will also produce pupil dilation along with cycloplegia.
