p.13
Beta and Alpha Blockers
What effects do nonselective beta blockers have due to inhibiting B2 receptors?
Bronchoconstriction and some vasoconstriction effects.
p.8
Reflexes in the Autonomic Nervous System
What happens when blood pressure (BP) is too high according to the medulla?
The medulla sends signals through the parasympathetic pathway via the vagus nerve to slow the heart rate (HR).
p.13
Beta and Alpha Blockers
Which two medications have both alpha and beta blocking effects?
Labetalol and carvedilol.
p.3
Neurotransmitters in the Autonomic Nervous System
What triggers the release of norepinephrine from sympathetic postganglionic neurons?
Calcium entering the nerve terminal.
p.8
Management of Autonomic Nervous System Disorders
What effect does phenylephrine have on blood pressure?
It increases systemic vascular resistance (SVR), leading to an increase in BP.
p.13
Beta and Alpha Blockers
What is unique about the metabolism of esmolol?
It is very fast on/off because it’s metabolized by plasma esterases.
p.3
Neurotransmitters in the Autonomic Nervous System
What are the three main mechanisms for removing norepinephrine from the synapse?
1. Reuptake into the nerve terminal, 2. Diffusion into circulation, 3. Uptake by local cells.
p.8
Management of Autonomic Nervous System Disorders
What is the role of anesthesia drugs like propofol and beta blockers on baroreceptor reflex?
They can impair the baroreceptor reflex, affecting the regulation of HR and BP.
p.13
Management of Autonomic Nervous System Disorders
What are the consequences of overdosing on beta blockers?
Severe hypotension, bradycardia, and/or bronchoconstriction.
p.3
Neurotransmitters in the Autonomic Nervous System
Which enzymes break down norepinephrine?
Monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT).
p.8
Reflexes in the Autonomic Nervous System
What is the Cushing reflex?
It occurs during intracranial hypertension, resulting in hypertension, bradycardia, and irregular respiration.
p.13
Management of Autonomic Nervous System Disorders
What treatments are available for beta blocker overdose?
Cardiac pacing, isoproterenol, glucagon, calcium, phosphodiesterase III inhibitors, and epinephrine.
p.9
Reflexes in the Autonomic Nervous System
What is the celiac reflex?
A reflex that occurs during laparoscopic surgery when the peritoneum is filled with gas, causing bradycardia and hypotension due to vagus nerve stimulation.
p.8
Reflexes in the Autonomic Nervous System
What does the Bainbridge reflex involve?
It increases HR when preload into the heart is high, inhibiting the vagus nerve.
p.3
Catecholamines and Their Effects
What is the ratio of epinephrine to norepinephrine produced in the adrenal medulla?
80% epinephrine to 20% norepinephrine.
p.9
Management of Autonomic Nervous System Disorders
What can be done to manage the celiac reflex during surgery?
Lower the pressure of gas or administer Robinul/atropine.
p.8
Reflexes in the Autonomic Nervous System
What occurs during the Bezold-Jarisch reflex?
When preload drops significantly, HR slows down to allow more time for blood to fill the heart.
p.1
Overview of the Autonomic Nervous System
What are the two main pathways of the autonomic nervous system?
Sympathetic and parasympathetic pathways.
p.13
G-Protein Coupled Receptors
What happens when a phosphodiesterase III inhibitor like milrinone is administered?
More cAMP remains in the cells, leading to increased heart rate and contractility.
p.3
Management of Autonomic Nervous System Disorders
What is pheochromocytoma?
A tumor on chromaffin cells at the adrenal gland that leads to excessive catecholamine release.
p.9
Adrenergic Receptors and Their Functions
What receptors does epinephrine bind to?
Beta 1, Beta 2, Alpha 1, and Alpha 2 receptors.
p.3
G-Protein Coupled Receptors
What role do G-proteins play in target cells?
They are receptors that initiate a series of events when activated.
p.1
Overview of the Autonomic Nervous System
What is the function of the ganglion in the autonomic nervous system?
It is the synapse or gap between preganglionic and postganglionic neurons.
p.9
Management of Autonomic Nervous System Disorders
What is the primary use of norepinephrine in the ICU?
It is the most common pressor used for most shock states, except for cardiogenic shock.
p.4
G-Protein Coupled Receptors
What are the two main effectors mentioned?
Adenylyl cyclase and phospholipase C.
p.6
Adrenergic Receptors and Their Functions
What physiological effects are associated with B2 receptor stimulation?
Vasodilation, relaxation of bronchioles, increased glucose levels, and insulin release.
p.9
Catecholamines and Their Effects
What effect does norepinephrine have at higher doses?
Increased vasoconstriction due to A1 and A2 stimulation, which can hinder the increase in heart rate.
p.4
G-Protein Coupled Receptors
What effect does activated Gi receptors have on adenylate cyclase?
They inhibit adenylate cyclase, blocking ATP from making cAMP.
p.4
G-Protein Coupled Receptors
What does activated Gq receptors stimulate?
Phospholipase C, leading to an increase in calcium, IP3, and DAG.
p.6
Neurotransmitters in the Autonomic Nervous System
What triggers the release of acetylcholine into the synapse?
Calcium influx through voltage-gated channels when the signal reaches the nerve terminal.
p.5
Adrenergic Receptors and Their Functions
What are some effects of stimulating Alpha 1 receptors?
Mydriasis, increased sweat gland activity, contraction of the uterus, decreased digestive motility, and increased serum glucose.
p.10
Synthetic Catecholamines
Why is Isoproterenol used in heart transplant patients?
Because their hearts are denervated and unresponsive to manipulation of the SA node via atropine.
p.2
Sympathetic vs. Parasympathetic Pathways
What is the primary function associated with the sympathetic nervous system?
Flight or fight response.
p.10
Synthetic Catecholamines
What is the clinical use of Ephedrine?
It increases both heart rate and systemic vascular resistance, useful in bradycardic and hypotensive patients.
p.11
Management of Autonomic Nervous System Disorders
How can selective Beta 2 agonists be used in pregnancy?
To delay premature labor by relaxing the uterus.
p.2
Sympathetic vs. Parasympathetic Pathways
Where do sympathetic pathways typically exit the spinal column?
In the thoracic or upper lumbar intervertebral spaces.
p.12
Alpha and Beta Blockers
What is the effect of blocking A2 receptors with yohimbine?
It increases the release of norepinephrine, raising blood pressure and heart rate.
p.2
Neurotransmitters in the Autonomic Nervous System
What is the rate-limiting step in the production of norepinephrine?
The conversion of tyrosine by the enzyme tyrosine hydroxylase.
p.12
Alpha and Beta Blockers
What type of antagonist is phentolamine?
A competitive antagonist of both A1 and A2 receptors.
p.12
Alpha and Beta Blockers
How can beta blockers be classified based on selectivity?
They can be selective for B1 or non-selective, blocking both B1 and B2.
p.12
Alpha and Beta Blockers
What effect do B1 selective drugs have on heart rate and contractility?
They decrease heart rate and contractility.
p.8
Reflexes in the Autonomic Nervous System
What is a common presentation of the Bezold-Jarisch reflex?
Bradycardia in the presence of hypotension and coronary artery dilation.
p.9
Adrenergic Receptors and Their Functions
What are the effects of epinephrine binding to B2 receptors?
Bronchodilation and vasodilation.
p.4
G-Protein Coupled Receptors
What initiates the G-protein signaling process?
A neurotransmitter (first messenger) binds to a G-protein receptor on the cell membrane.
p.1
Sympathetic vs. Parasympathetic Pathways
How do sympathetic pathways differ from parasympathetic pathways in terms of neuron length?
Sympathetic pathways have shorter preganglionic neurons and longer postganglionic neurons.
p.9
Catecholamines and Their Effects
What happens to heart rate and contractility at low doses of norepinephrine?
B1 stimulation increases heart rate and contractility.
p.7
Adrenergic Receptors and Their Functions
What effect do M3 receptors have in the lungs?
They cause bronchoconstriction when stimulated.
p.1
Sympathetic vs. Parasympathetic Pathways
What happens at the effector organ in the parasympathetic pathway?
The presynaptic nerve synapses to a short postganglionic neuron.
p.5
Adrenergic Receptors and Their Functions
What are the main adrenergic receptors?
Beta 1 (B1), Beta 2 (B2), Alpha 1 (A1), and Alpha 2 (A2).
p.7
Adrenergic Receptors and Their Functions
What is the role of the M2 receptor in the heart?
It lowers heart rate when acetylcholine binds to it.
p.6
Neurotransmitters in the Autonomic Nervous System
How is acetylcholine produced in cholinergic neurons?
By combining choline with acetyl CoA made in the mitochondria.
p.5
Adrenergic Receptors and Their Functions
What physiological effect occurs when A1 receptors are stimulated in the vascular system?
Rise in blood pressure due to constriction of blood vessels.
p.10
Synthetic Catecholamines
What receptors are stimulated as the dose of dopamine increases?
B1 receptors are stimulated first, followed by A1 receptors at higher doses.
p.11
Catecholamines and Their Effects
Why doesn't vasopressin work well in septic or heart transplant patients?
Because it stimulates the release of natural catecholamines.
p.10
Synthetic Catecholamines
What are the effects of Isoproterenol?
Increased heart rate, contractility, and bronchodilation, along with vasodilation from B2 effects.
p.10
Synthetic Catecholamines
What is the role of Isoproterenol in heart transplant patients?
Acts as a chemical pacemaker for the heart.
p.10
Synthetic Catecholamines
What is the primary action of Phenylephrine?
It is specific for A1 receptors and causes an increase in blood pressure due to increased systemic vascular resistance (SVR).
p.10
Synthetic Catecholamines
When would you administer Phenylephrine?
When you want to increase afterload and lower heart rate.
p.2
Sympathetic vs. Parasympathetic Pathways
What are some physiological responses of the sympathetic nervous system?
Increased heart rate, blood pressure, bronchodilation, increased metabolic rate, and decreased digestive activity.
p.2
Sympathetic vs. Parasympathetic Pathways
Where do parasympathetic pathways originate?
From cranial nerves (e.g., vagus) or through sacral intervertebral spaces.
p.12
Alpha and Beta Blockers
What type of antagonist is phenoxybenzamine?
A non-competitive antagonist of both A1 and A2 receptors.
p.12
Alpha and Beta Blockers
What is the result of blocking A1 and A2 receptors with phenoxybenzamine?
Vasodilation occurs, but norepinephrine release increases heart rate due to B1 receptor binding.
p.12
Alpha and Beta Blockers
What is the rule for determining B1 selectivity based on the drug name?
If it starts with a letter from the first half of the alphabet, it's B1 selective; the second half is non-selective.
p.1
Overview of the Autonomic Nervous System
What is the primary goal of the sympathetic and parasympathetic pathways?
To maintain homeostasis in the body.
p.9
Catecholamines and Their Effects
How does the effect of epinephrine change with dosage?
At low doses, it favors beta receptors; at higher doses, it favors alpha receptors.
p.6
Adrenergic Receptors and Their Functions
What are the primary locations of B1 and B2 receptors?
B1 receptors are in the heart, and B2 receptors are in the lungs and other areas.
p.1
Sympathetic vs. Parasympathetic Pathways
Where do most ganglions of the sympathetic nervous system reside?
Right off the spinal cord, forming the ganglionic chain.
p.9
Management of Autonomic Nervous System Disorders
What is a risk associated with infusing norepinephrine through a peripheral IV?
It can cause necrosis to local tissue if the IV infiltrates.
p.1
Overview of the Autonomic Nervous System
What is the pathway from the brain to the liver in the autonomic nervous system?
A neuron starts in the brain, travels down the spinal cord, and synapses at the liver.
p.10
Synthetic Catecholamines
What is the effect of low doses of dopamine on the kidneys?
It causes renal vasodilation and increased blood flow to the kidneys.
p.7
Reflexes in the Autonomic Nervous System
Where are the pressure sensors for the baroreceptor reflex located?
In the carotid sinus and the transverse aortic arch.
p.4
G-Protein Coupled Receptors
How does cAMP affect different cell types?
It causes different effects depending on the type of cell.
p.11
Neurotransmitters in the Autonomic Nervous System
Where is vasopressin naturally made and stored?
Made in the hypothalamus and stored in the posterior pituitary gland.
p.11
Adrenergic Receptors and Their Functions
What effect does vasopressin have on blood vessels?
Causes vasoconstriction due to vasopressin 1 (V1) receptors.
p.11
Neurotransmitters in the Autonomic Nervous System
What is the role of vasopressin 2 (V2) receptors?
They cause water to be reabsorbed in the collecting ducts of the kidney.
p.11
Management of Autonomic Nervous System Disorders
When should vasopressin be administered?
If other pressors are not working, or as first line if the patient is on ACE inhibitors or ARBs.
p.11
Catecholamines and Their Effects
What is the primary effect of dobutamine?
Increases heart rate and contractility, making it great for cardiogenic shock.
p.11
Adrenergic Receptors and Their Functions
What is the purpose of selective Beta 2 agonists like albuterol?
To stimulate B2 receptors for bronchodilation with limited effect on heart rate.
p.12
Alpha and Beta Blockers
What effect do selective A1 blockers have on blood vessels?
They cause vasodilation due to decreasing systemic vascular resistance (SVR).
p.11
Adrenergic Receptors and Their Functions
How do Alpha 2 agonists lower blood pressure?
By inhibiting norepinephrine release from neurons, resulting in vasodilation.
p.2
Neurotransmitters in the Autonomic Nervous System
What are the main neurotransmitters for the sympathetic nervous system?
Norepinephrine and epinephrine.
p.2
Neurotransmitters in the Autonomic Nervous System
How is norepinephrine stored in neurons?
It is packaged in vesicles at the nerve terminal until stimulated for release.
p.12
Alpha and Beta Blockers
What conditions are beta blockers typically used for?
Coronary artery disease, congestive heart failure, and hypertension.
p.6
G-Protein Coupled Receptors
What happens to cAMP levels when protein pathways are activated in certain cells?
cAMP will be reduced, causing more contraction in this cell type.
p.6
Adrenergic Receptors and Their Functions
What is the initial effect of administering a bolus of precedex?
A transient increase in blood pressure due to peripheral vasoconstriction.
p.4
G-Protein Coupled Receptors
What happens to the alpha subunit of the G-protein after activation?
It detaches from the G-protein and activates or inhibits an effector protein.
p.6
Adrenergic Receptors and Their Functions
What effect do B1 receptors have on the heart?
They increase heart rate and contractility of the myocardium.
p.6
Adrenergic Receptors and Their Functions
What is the primary function of B2 receptors?
They cause bronchodilation and relaxation/dilation of various muscles.
p.4
G-Protein Coupled Receptors
What is a common second messenger activated by Gs receptors?
Cyclic adenosine monophosphate (cAMP).
p.7
Reflexes in the Autonomic Nervous System
What is the function of the baroreceptor reflex?
To maintain homeostasis by regulating blood pressure.
p.7
Reflexes in the Autonomic Nervous System
Which nerves send signals from the carotid sinus and transverse aortic arch?
Glossopharyngeal nerve and vagus nerve, respectively.
p.5
Adrenergic Receptors and Their Functions
What is the effect of stimulating Alpha 2 receptors?
Inhibition of adenylate cyclase, leading to less cAMP production.
p.5
Adrenergic Receptors and Their Functions
What role does norepinephrine play in the function of Alpha 2 receptors?
It acts as a first messenger and can cause a negative feedback loop to decrease additional norepinephrine release.
p.5
Adrenergic Receptors and Their Functions
What are some effects of Alpha 2 receptor stimulation?
Sedation, anti-shivering effects, decreased insulin release, increased platelet aggregation, diuresis, and vasoconstriction.
p.5
Adrenergic Receptors and Their Functions
Why does vasoconstriction occur with Alpha 2 receptor stimulation?
Some A2 receptors are located in the smooth muscles of blood vessels, allowing norepinephrine to bind and cause vasoconstriction.
p.10
Synthetic Catecholamines
How does Ephedrine act?
By both direct and indirect stimulation of alpha and beta receptors.
p.11
Catecholamines and Their Effects
What are some effects of selective Beta 2 agonists?
Decreased potassium, vasodilation, and increased glucose/insulin.
p.2
Sympathetic vs. Parasympathetic Pathways
What are some physiological responses of the parasympathetic nervous system?
Decreased heart rate, increased digestive tract movement, and increased sexual arousal.
p.12
Alpha and Beta Blockers
What is the primary use of A1 selective blockers?
They are commonly used in patients with benign prostatic hypertrophy.
p.11
Management of Autonomic Nervous System Disorders
What is a notable feature of Alpha 2 agonists regarding respiratory drive?
They have a limited effect on respiratory drive, making them nice sedative drugs.
p.12
Alpha and Beta Blockers
What is the primary function of beta blockers?
To decrease strain on the heart by lowering heart rate and/or contractility.
p.12
Alpha and Beta Blockers
What are the exceptions to the B1 selectivity naming rule?
Metoprolol is B1 selective, and carvedilol is non-selective.
