Vasopressors Flashcards
End organ damage occurs when map is below 50 for ___
1 minute
End organ damage occurs when MAP is below 65 for ____
13-28 minutes
What is the difference between autonomic and somatic ANS?
Somatic does not involve ganglia, ACH goes directly to the nicotinic receptor
Sympathetic innervation of the adrenal medulla
ACH binds to the nicotinic receptor on the adrenal medulla (instead of the post ganglionic neuron), then epinepherine is released into the blood to bind on to adrenergic receptors
Sympathetic innervation
ACH binds to the nicotinic receptor on the post ganglionic neuron which releases norepinepherine to bind to adrenergic receptors
Parasympathetic innervation
ACH binds to the nicotinic receptor on the post ganglionic neuron which releases ACH to bind to muscuranic receptors
Sympathetic nervous system origin
T1-L2
Preganglia near spinal cord
Postganglia secrete norepinepherine
What converts dopamine to norepinephrine?
Beta Hydroxylase
What releases NE from the synaptic vessel?
Action potential
Signal termination of NE
Reuptake
Metabolism by MAO and COMT
Dilution by diffusion
Location of adrenergic receptors
A1- periphery
A2- Presynaptic in the PNS, postsynaptic in the CNS
B1- heart
B2- smooth muscle
A1 receptor works by __
Increase intracellular Ca++
Smooth muscle contraction
Peripheral vasoconstriction
Bronchoconstriction
- insulin
+glycogenolysis
+gluconeogenesis
Mydriasis
GI relaxation
A2 works in the presynaptic PNS by ____
Decreases Ca++ into cell
Limits release of NE
A2 in the postsynaptic CNS
Sedation
Decreases BP
Decreases sympathetic outflow
Platelet aggregation
B-1 works to __
Increases chronotropy
Increases dromotropy
Increases inotropy
B2 works by __
Smooth muscle relaxation
Peripheral vasodilation
Decreases BP
+ insulin
+ glycogenolysis
+ gluconeogenesis
Decreases GI mobility
Parasympathetic nervous system origins
Craniosacral origin (3,7,9,10)
ACH
Activates BOTH arms of ANS
Ca++ mediated action potential
Formed by choline and acetyltransferase
Deactivated by acetylcholinesterase
SNS effect on GI system and bladder
Decreases motility
Constricts sphincter
Relaxes smooth muscle in bladder, but contracts sphincter
ANS effect on GI and bladder
Increases motility, relaxes sphincter
Contracts bladder smooth muscle, relaxes sphincter
Down regulation
Long process of destruction of receptors
Extended exposure to agonists will reduce the number of receptors
Tachyphylaxis
Up regulation
Chronic depletion of catecholamines or beta blockers will increase the amount of receptors but not their sensitivity
Tachyphylaxis
Decreased effectiveness due to chronic exposure
Happens with down regulation
Receptor uncoupling
Rapid inability of the receptor to bind to the G protein
Sequestration
Slowly move receptors inside the cell
Pheocromocytoma
Uncontrolled release of catecholamines due to adrenal gland dysfunction
Uses of sympathomimetics
Positive inotropy
Elevate blood pressure
Treat bronchospasms
Manage anaphylaxis
Arrhythmia management
Addition to LA to slow systemic absorbtion
Types of sympathomimetics
Naturally occurring catecholamines (direct)
Synthetic catecholamines
Synthetic non catecholamines (direct and indirect)
What are sympathomimetics derived from?
B Phenylethlamine
Catecholamines vs synthetic non catecholamines
Sympathomimetics (synthetic non catecholamines) do not have the hydroxyl group in the 3 and 4 position of benzene ring