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Flashcards in Adrenergic Blockers Deck (21)
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1

What are the three ways to block adrenergic neurotransmission?

1. Decreasing sympathetic outflow from brain

2. Suppressing norepinephrine release from presynaptic neurons

3. Blocking postsynaptic adrenergic receptors

2

Two mechanisms that alpha-2 adrenergic receptors inhibit sympathetic neurotransmission

1. Postsynaptic receptors inhibit sympathetic neurons that exit the brain

2. Presynaptic receptors inhibit NE release

3

4

Effect of alpha antagonists on heart

Vasodilation-Increases HR because compensates for postural hypotension

5

Effect of beta-2 blockers

Increase intraocular pressure and exacerbate asthma symptoms worldwide

6

Use of beta 2 blockers

NEVER

7

Competitive antagonists to adrenaline

Tolazoline

8

Non-competitive/covalent antagonist to adrenaline

Phenoxybenzamine (only for life-threatening)

9

Adrenoceptor block effect on heart

Prevents increase in HR in response to threats, pacemakers continue regardless (susceptible to disease), must use echo/stress test first!

10

Adrenoceptor block effect on CV

Decreased PR

11

Phaeochromocytoma

Endless secretion of catecholamines, treated by alpha adrenoceptor antagonists

12

Effect of beta adrenoceptor blockers on heart

Increased contraction of the heart demands more oxygen (can't in CAD-->hypoxemia, necrosis)

13

Most potent treatment of glaucoma

Timolol

14

Which is used more, propramolol or atenolol?

Propramolol has greater safety and we know it works, atenolol tests still underway (but may become more common later)

15

Renin effect on body

More renin in body-->constricted arteries, more fluid in kidneys, more absorbed into circulation instead of released from body

16

Betablockers affect on renin

Decrease renin, less water retention-->lower BP

17

Mechanism of Clonidine and guanabenz

Suppress sympathetic outflow from brain by binding to alpha-2 adrenergic receptors

18

Alpha-methyl-norepinephrine (MeNA) mechanism

Metabolized in presynaptic neuron from methyldopa, released as alpha-2 agonist

19

Peripheral presynaptic anti-adrenergics mechanism

Inhibit NE release from presynaptic terminal

20

Guandadrel and reserpine

Peripheral Presynaptic anti-adrenergics that deplete NE from presynaptic vessels

21

Mechanism of alpha blockers

Compete with endogenous catecholamines for binding at alpha1 and 2 receptors, inhibited catecholamine action