Flashcards in Pharm 5 Lecture Deck (79)
What is the main sympathetic nervous system neurotransmitter?
What is released from the adrenal medulla (when stimulated by SNS) as a HORMONE?
hormones made by the adrenal glands, release when a person is under physical or emotional stress, high potency, quick duration, does not penetrate BBB, easily broken down, can't be taken orally
What are some examples of catecholamines?
What are the 6 steps of adrenergic neurotransmission?
1. Synthesis of norepi
2. uptake into storage vessicles
3. release of neurotransmitter
4. binding to receptor
5. removal of norepi
What is the rate-limiting step of the synthesis of norepinephrine?
Hydroxylation of tyrosine into DOPA (dihyro-Phenoxyalanine)
What is the main precursor to epinephrine?
When is dopamine converted to norepinephrine?
Inside the vessicle; where it is protected from degradation
What inhibits transport of dopamine into the vessicle?
What causes fusion of the vesicle containing norepi with the cell membrane in a process known as exocytosis?
Influx of calcium causes the fusion
What blocks the release of the vesicle containing norepi?
Guanethidine and bretylium
What prevents reuptake of norepinephrine?
Cocaine and imipramine
What metabolizes norepineprhine?
Methylated by Catecol-O-methyl transferase (COMT)
Oxidized by Monoamine oxidase (MAO)
How does DOPA --> Dopamine?
Dopa is decarboxylated
A direct acting synthetic catecholamine
Alpha Adrenoceptors in order of affinity
Highest Affinity: Epinephrine
Beta Adrenoceptors in order of affinity
Highest affinity: Isoproterenol
What are the names of the dopaminergic receptors?
D1, D2, D3, D4, D5
A1 receptors have a relatively high affinity for....
A2 receptors have a high affinity for....
Clonidine (Catapres), an antihypertensive drug
What does alpha 1 innervate?
Smooth muscle of most non-cardiac origin
What are the effects of stimulating alpha 1?
vasoconstriction; increased bp
mydriasis (dilation of pupils)
increased bladder tone
increased tension in prostate
What are the effects of stimulating alpha 2?
Creates negative feedback loops (prejunctional nerve terminals)
Some GI and digestive effects
Where are alpha 2 receptors located?
Prejunctional nerve terminals
Why would we stimulate alpha 2?
Increasingly used in human cardiovascular surgery as a sedative as part of multi-modal anesthesia
What are some advantages to stimulating alpha 2 during srugery?
Modulates DPB-induced inflammatory responses better than glucocorticoids (such as a cortisol)
Sympatholytic effects help ameliorate unwanted CV reflexes post-op
less respiratory depression postop than other options
What is the one alpha 2 drug used in humans?
What has affinity for Beta 1 receptors?
Equal affinity for norepinephrine and epinephrine (both less than isoproterenol)