Sepsis/SIRS Flashcards
Why do owners need to wear gloves when giving Chloramphenicol?
May cause idiosyncratic aplastic anemia
Which ampicillin is antipseudomonal penicillin?
Piperacillin-tazobactam
True or False: Most of the NE produced by adrenal glands are converted to epinephrine after being released to the blood stream.
True
About 80% NE are converted to epinephrine
Name a condition when “spillover” of NE can be observed.
Heart failure
where chronically elevated sympathetic tone cause NE “spillover” from the synaptic cleft into the bloodstream.
What are the two major pre-synaptic adrenoreceptors?
𝜶2A/D - inhibitory effect
𝜷2 - stimulatory effect
What are the 9 subtypes adrenoreceptors?
𝜶1A, 𝜶1B, 𝜶1D
𝜶2A/D, 𝜶2B, 𝜶2C
𝜷1, 𝜷2, 𝜷3
True or False: 𝜶1 receptors generally have stronger affinity to epinephrine than NE, while 𝜶2 receptors are the opposite.
False
True or False: 𝜷1 receptors have equal affinity to epinephrine and NE, while 𝜷2 receptors have much stronger affinity to epinephrine than NE.
True
𝜷2 receptors are pretty much exclusively to Epi
True or False: In most tissues, 𝜶1 receptor subtypes are junctional, and 𝜶2 receptor subtypes are extra-junctional.
True
Which 𝜶2 receptor subtypes locate at the pre-synaptic region and endothelium and cause vasodilation?
𝜶2A/D
Which G protein does 𝜶1, 𝜶2 and 𝜷 receptor subtypes usually couple with? are they stimulatory or inhibitory?
𝜶1: Gq/11 protein → activate phospholipase C → release non-mitochondrial intracellular Ca stores
𝜶2: Gi protein → inhibits adenylate cyclase → inhibit conversion of cAMP from ATP → inhibits protein kinase A → inhibit voltage-gated Ca channels
𝜷: Gs protein → activates adenylate cyclase → convert ATP to cAMP → activates protein kinase A → open voltage-gated Ca channels
True or False: 𝜶1A/D receptors are responsible for large arterial vasoconstriction, and 𝜶1B receptors are responsible for smaller arteries and arterioles as well as induces vascular smooth muscle growth and/or hypertrophy.
True
What is the main difference in the 𝜶 receptor subtypes distribution between artery and venous?
Artery: 𝜶1 receptors are junctional and 𝜶2 receptors are extra-junctional
Venous: 𝜶2 receptors are junctional and 𝜶1 receptors are extra-junctional → 𝜶2 receptors is the predominate one managing vasoconstriction
Which adrenoreceptors on the endothelium stimulate NO production and subsequent vasodilation?
𝜶2A/D
What is the density of 𝜶1 receptor subtypes on the myocardium compared to 𝜷?
𝜶1A receptor subtypes 10-15% of 𝜷 receptors
𝜶1A receptor subtypes is responsible for about 25% of inotropy
True or False: 𝜷1 receptors activation at the heart increase inotropy (contractility), chronotropy (HR), lusitropy (relaxation) and dromotropy (AV node conduction).
True
What is the effect of 𝜷 receptors at the vascular system?
Vasodilation
What is the effect of 𝜶 receptors and 𝜷 receptors on the coronary system?
𝜶 receptors - vasoconstriction
𝜷 receptors - vasodilation
What is the predominant 𝜷 receptor subtypes on the endothelium?
𝜷2 receptor
Stimulation of which adrenoreceptors will cause renin release? which one will cause inhibition of renin release?
𝜷1 → renin release
𝜶2 → inhibition of renin release
Both receptors locate at JXA
What is the role of 𝜷-agonist receptor kinase (𝜷-ARK).
When 𝜷 receptors are activated, 𝜷-ARK are activated to catalyze the 𝜷 receptors
Sustained stimulation of 𝜷 receptors → lots of 𝜷-ARK → 𝜷 receptors down regulation (both 1&2)
The remaining 𝜷 receptors will become uncoupled
Uncoupled 𝜷1: mediate myocardial apoptosis
Uncoupled 𝜷2: inhibit apoptosis
Rank the following effects on each receptor
Drug: Dobutamine, Epinephrine, Norepinephrine, Phenylephrine
𝜶1&2
𝜷1
𝜷2
𝜶1&2: Epi = NE = phenylephrine > Dobutamine (weak)
𝜷1: Epi > Dobutamine > NE (weak) > phenylephrine (none)
𝜷2: Epi > Dobutamine (weak)> Epi (none) = phenylephrine (none)
True or False: When 𝜶 agonist is used alone, it can decrease cardiac output.
True
How does vasopressin increase blood pressure (3 mechanisms)?
1) Bind to V1 receptor → increase intracellular Ca level via phosphatidylinositol-bisphosphonate cascade
2) Bind to V1 receptor → inhibit IL-𝜷 induced production of NO and cGMP, as well as iNOS mRNA expression
3) Blocks K+-sensitive ATP channels (normally activated with endotoxemia) → decreasing the amount of K+ flux and subsequently opening the voltage-dependent Ca channels → increase intracellular Ca level