Pharmacology - alpha1 blockers and alpha2 agonists

Question 1

true or false

binding Gq causes vasoconstriction

Answer 1

true

causes calcium release and vasoconstriction

Question 2

drugs that mimic the action of ___ or ___- have been termed sympathomimetic drugs

Answer 2

epinephrine or norepinephrine

Question 3

alpha 1 receptors work through what GPCR?

what about alpha 2?

Answer 3

alpha 1 - Gq

alpha 2 - Gi

Question 4

what does NE binding to alpha 1 receptors do to:

-blood vessels
-pupils
-urinary sphincter

Answer 4

CONTRACTS THEM

causes contraction of blood vessels (increased peripheral resistance)

dilation of pupils

contraction of sphincter, causing decreased urination

Question 5

name 3 alpha 1 adrenergic blockers****

Answer 5

prazosin
doxasozin
terazosin

Question 6

name 2 alpha 2 agonists

are they centrally acting?

Answer 6

yes

clonidine, methyldopa

Question 7

rank the following according to their binding affinity to the alpha adrenoceptor:

-norepinephrine
-isoproterenol
-epinephrine

Answer 7

most - epi, then nor, least is isopoterenol

Question 8

rank the following according to their affinity to bind the BETA adrenoceptor:

epinephrine
norepinephrine
isoproterenol

Answer 8

most - isoproterenol
epi
least is norepi

Question 9

true or false

too much calcium supplementation will lead to Hypotension

Answer 9

FALSE

hypertension

Question 10

alpha and beta adrenoceptors are what class of receptor?

Answer 10

GPCRs

Question 11

when INACTIVE, the Gq receptor is bound to GTP or GDP?

Answer 11

GDP

bound to GTP when active

Question 12

where are alpha 1 receptors located

Answer 12

the blood vessels

Question 13

when the alpha 1 receptors are stimulated by epinephrine or norepinephrine, what happens??

Answer 13

they constrict

Question 14

true or false

when stimulated, Gq coupled receptors decrease calcium release

Answer 14

FALSE - increase

Question 15

true or false

stimulation of alpha 1 receptors by epi or norepi causes both pyloric sphincter contraction and urinary sphincter contraction

Answer 15

TRUE

thus decreases digestion and urination

Question 16

explain how alpha 1 blockers like terazosin, prazosin, and doxazosin work in terms of blood pressure

Answer 16

they reduce the peripheral resistance by inhibiting constriction, and thus lower BP

Question 17

true or false

prazosin, terazosin, and doxazosin are SPECIFIC for blocking alpa 1

Answer 17

TRUE

Question 18

name some AE of alpha adrenergic blockers

Answer 18

postural hypotension
fluid retention
dry mouth
males cant ejaculate

Question 19

first-dose effect of prazosin

Answer 19

syncopy (fainting) and depression

Question 20

**aside from treating high blood pressure, what else can terazosin and other alpha 1 blockers treat????

Answer 20

BPH (benign prostatic hyperplasia)

bc they will RELAX the smooth muscle of the prostate

Question 21

true or false

with other antihypertensive agents, alpha 1 blockers can cause hypotension

Answer 21

true

Question 22

is there any DDI concern with alpha 1 blockers

Answer 22

yes - with other highly protein bound drugs like sulfa antibiotics, NSAIDS

Question 23

alpha 2 agonists inhibit the….

Answer 23

sympathetic nervous system

Question 24

true or false

alpha-methyldopa is a prodrug

Answer 24

true

Question 25

alpha-methyldopa is a precursor of ___ and ___

Answer 25

dopamine and norepinephrine

rate limiting step to make NE

Question 26

agonists binding to alpha 2 cause what

Answer 26

inhibitory effects (works through Gi) at presynaptic nerve terminals

inhibits sympathetic nervous system

Question 27

alpha-methyldopa, and a2 agonist, is not used therapeutically now, except in…….

Answer 27

hypertension during pregancy

Question 28

clonidine is not frequently used now whY?

Answer 28

bc of tolerance and withdrawal hypertension

Question 29

explain the MOA of clonidine and how the BP is lowered

Answer 29

when synaptic NE levels rise at the presynaptic nerve ending, clonidine binds to the alpha 2 receptors IN THE BRAIN to shut down NE release through feedback inhibition

this results in decreased cardiac output and some decreased peripheral resistance, as well as potentially inhibitng renin release

Question 30

true or false

clonidine increases the firing of sympathetic nerves

Answer 30

FALSE

decreases

Question 31

clonidine binds at what specific site in the brain

Answer 31

the depressor site of the vasomotor center

Question 32

**aside from treating hypertension, what else is clonidine/catepres used for

Answer 32

to help with nicotine and narcotic withdrawal symptoms

Question 33

explain the MOA of methyldopa to help decrease BP

Answer 33

it acts as a false substitute of dopa.

this will form a FALSE norepinephrine called alpha methyl norepinephrine

thus, when this false NE binds to a2, it will NOT cause vasoconstriction like NE would

Question 34

**which are true??

to lower BP you need:

-a1 agonist
-a2 agonist
-a1 blocker
-a2 blocker

Answer 34

alpha 2 agonist

a1 blocker