Vasoconstrictors - Quiz 1 Flashcards
What ocurrs w/ the Sympathetic Stimulation of the Adrenal Medulla?
ACh binds to Nicotinic Receptor in the Adrenal Medulla, which then releases Epinephrine into the Blood to bind to Adrenergic Receptors
How does Sympathetic Stimulation release Norepinephrine?
Ach binds to Nicotinic Receptor on the Postganglionic Neurons, releasing Norepi to bind to Adrenergic Receptors
What happens w/ Autonomic Parasympathetic Stimulation?
ACh binds to Nicotinic Receptors on the Postganglionic Neurons, and ACh is released to bind to Muscarinic Receptors.
What is the difference b/t Somatic & Autonomic Response?
With Somatic, ACh is released and binds to Nicotinic Receptors in muscles WITHOUT Ganglia involvement
Which enzyme breaks down Dopamine into Norepi?
Beta Hydroxylase
What causes a release of Norepi from the Synaptic Vessel?
An Action Potential
What are the ways in which the Norepi Signal is Terminated?
Reuptake - 80%
Dilution - 20%
Monamine Oxidase (MAO)
Catechol-o-Methyltransferase (COMT)
Where are Alpha-1 Receptors located?
Periphery
Where are Alpha-2 Receptors Located?
Central
Where are Beta-1 Receptors located?
Heart
Where are Beta-2 Receptors Located?
Smooth Muscle
What happens when the Alpha-1 Receptor is activated?
↑Intracellular Calcium
Contract Smooth Muscle
Vaso & Bronchoconstriction
Inhibit Insulin
Breaks Down Glycogen
Gluconeogenesis
Relaxes GI
Dilates Pupils
What happens w/ the activation of Alpha-2 Receptors in the Presynpatic PNS?
↓Calcium Entry
&
↓Norepi Release
What happens w/ the activation of Alpha-2 Receptors in the Postsynaptic CNS?
Sedation
↓Sympathetic Outflow
↓BP
Platelet aggregation
What happens when Beta-1 Postsynaptic Receptors are activated?
Increases HR, Contractility, and Conduction Velocity
What happens when Beta-2 Postsynaptic receptors are activated?
Relax Smooth Muscles
Vaso & Bronchodilation
↑Insulin
↑Glycogen Breakdown
↑Gluconeogenesis
↓GI Motility
Which Autonomic System does Acetylcholine activate?
BOTH SNS & PNS
What is Tachyphylaxis?
Diminishing response to successive doses of a drug - happens w/ over exposure to agonists
What is Receptor Uncoupling?
Receptor CANNOT bind to G Protein - happens fast
What is Sequestration in regards to Receptor Down Regulation?
Receptors move from Cell Surface to Inside the Cell - happens slower than Uncoupling
What is happens to the receptors during Downregulation?
Receptors move from Cell Surface to inside the cell, then DESTROYED - very slow process
What is Pheochromocytoma?
Uncontrolled release of Catecholamines d/t adrenal tumor
Catecholamines are considered BOTH ______ & ______ that act on adrenergic receptors
Catecholamines are considered BOTH Neutrotransmitters & Hormones that act on adrenergic receptors
How are Sympathomimetics different from Catecholamines?
Same benzene ring, but DOES NOT have Hydroxyl Groups at the 3 & 4 Position
What enzyme can break down Sympathomimetics?
Only Monamine Oxidase (MAO)
(CANNOT go thru Reuptake)
The inhibition of which Signal Termination mechanism would cause the greatest potentiation of Epinephrine?
Reuptake
How does the metabolism rate of Synthetic Non-Catecholamines compare to that of Catechols?
Slower
What kind of reactions are involved w/ the metabolism of Catecholamines & Phenylephrine?
Sulfoconjugation Reactions
Vasoconstrictors _______ Venous Return, Preload, and Cardiac Output
Vasoconstrictors INCREASE Venous Return, Preload, and Cardiac Output
What are the Reflex changes caused by Vasoconstrictors?
↓HR
↓Conduction
↓Contractility
What are the Non-Cardiac effects of Vasoconstrictors?
Bronchodilation
Glycogenolysis
CNS & Endocrine Stimulation
How long can a person have a MAP of <65 mmHG before having End Organ Damage?
13 - 28 min
How long can a person have a MAP of < 50 mmHg before having End Organ Damage?
1 Minute
What are complications of using Vasoconstrictors?
Ventricular Failure
↓Renal Blood Flow
Masks Hypovolemia
Which receptors does Epinephrine work on?
All of them - Alpha-1, Beta-1, Beta-2
How much more potent is Epinephrine than Norepi?
2-10x more potent
How does Epinephrine affect Blood Sugar?
↑Blood Sugar d/t decreased insulin secretion
How does Epinephrine affect the kidneys?
↓Renal Blood Flow
&
Stimulates Renin Release
Which receptor does Epinephrine act on at lower doses (1-2 mcg/min)?
Beta-2 in periphery, decreasing the SVR for better oyxgen exchange, but MAP stays the same
At what dose of Epinephrine are the Beta-1 receptors stimulated?
Intermediate dose - 4 mcg/min
Increases HR, Contractility, CO, and Automaticity
What happens w/ High doses of Epinephrine?
Potent Alpha-1 Stimulation causing vasoconstriction & can override the other receptor effects
Reflex Bradycardia
No CNS effects
What are the risks of using Racemic Epinephrine?
Tachy Arrythmias
&
Rebound Airway Edema
Which receptors does Norepi work on?
Alpha-1 > Beta-1
No Beta-2
Why do Lower doses of Norepi increase Cardiac Output, but Higher doses decrease Cardiac Output?
Increased Afterload causes Reflex Bradycardia
What receptors does Ephedrine work on?
Indirect & Direct Alpha-1 & Beta
Works on the Heart like Norepi w/ a little more HR effect
↑Contractility
What happens with continued use of Ephedrine?
Tachyphylaxis
How does Ephedrine affect the Uterus & Bronchial Smooth Muscle?
↑Uterine Blood Flow
&
Relaxes Bronchial Smooth Muscle
How does Ephedrine compare to Epinephrine regarding BP response?
Ephedrine’s BP Reponse is Weaker, but Longer Lasting
What are Ephedrine side effects?
Insomnia
Urinary Retention
Tremor
Psychosis
Palpitations
How does Cocaine & Amphetamines affect Ephedrine?
Blocks Reuptake –> Exaggerate HTN & Arrythmias
Which receptor does Phenylephrine work on?
Direct Alpha-1 to ↑Preload > Afterload
&
Small Beta-1
Other than Blood Pressure, what else is Phenylephrine used for as treatment?
Priapism
Nasal Decongestant
Mydriasis - Pupil Dilation
How does Phenylephrine affect the Pulmonary Vasculature?
↑PA Pressure & Resistance
How does Phenylephrine compare w/ Norepi?
Phenylephrine is Weaker, but Longer Lasting
How does DDAVP compare to Vasopressin regarding Antidiuretic Effect & Pressor Effect?
DDAVP is a much stronger Antidiuretic & has No Pressor Effect
How is Vasopressin different from Catecholamines?
Vasopressin can work in Hypoxic & Acidic environments
Which receptors does Vasopressin work on?
V1a - Pressor Effect
V2 - Antidiuretic Effect
What are the effects of Vasopressin in the setting of Cardiac Failure?
Cardiac Ischemia
↑Preload & ↑Afterload
↑Wall Stress
LVH
What is the advantage of using Vasopressin over Epinephrine?
Vasopressin is just as effective, but has no direct effect on HR & O2 Consumption
How should weight loss products that contain Ephedrine be managed peri-operatively?
Tachyphylaxis - Hold for 24 hrs before surgery
What is the treatment for Vasoconstrictor Extravasation?
Phentolamine - Alpha 1 & 2 Antagonist
What does Giapreza (Angiotensin II) do?
Vasoconstriction & ↑Aldosterone Release
What are the complications of using Giapreza (Angiotensin II)?
DVT
Tachycardia
Delirium
Thrombocytopenia