31: Vascular function and vasoactive drugs

Question 1

contractile state is controlled by

Answer 1

endothelium
circulating hormones
sympathetic nerves

Question 2

rise in Ca2+ activates ____which _____ myosin, ____ crossbridging with actin to ______contraction

Answer 2

MLCK
phosphorylates
enabling
initiate

Question 3

____ dephosphorylates MLC leading to ___

Answer 3

MLCP

relaxation

Question 4

inhibition of ____ maintains contraction

Answer 4

myosin phosphatase

Question 5

agents cause contraction by

Answer 5

releasing intracellular Ca2+ by IP3
depolarizing membrane and opening VG Ca2+
increasing MLKC/ decreasing MLCP

Question 6

agents cause relaxation by

Answer 6

inhibiting Cca2+ entry via VGCC or hyperpolarizing the membrane by opening K+
increasing intracellular cAMP and cGMP

Question 7

what does cAMP do

Answer 7

activates MLCP and promotes Ca2+ efflux

Question 8

what does cGMP do

Answer 8

activates MLCP and opposes agonist induced Ca2+ increase

Question 9

major vasodilators produced by endothelial cells (5)

Answer 9

NO (EDRF)
prostanoids (PGI2)
EDHF
Ca2+ activated K+ channels
CNP

Question 10

major vasoconstrictors produced by endothelial cells

Answer 10

endothelin
TXA2
angiotensin II

Question 11

is endothelin an hormone or local mediator

Answer 11

local meditor

Question 12

what does endothelin bind

Answer 12

ETa receptors expressed by VSMC

Question 13

endothelin causes ___ by

Answer 13

vasoconstriction

IP3 mediated Ca2+ release

Question 14

RAS stimulates ___ and salt water retention by kidney via _______

Answer 14

vasoconstriction

aldosterone

Question 15

drugs affecting RAS are used in treating

Answer 15

hypertension and heart failure

Question 16

ADH is secreted by

Answer 16

post pit

Question 17

ADH vauses ___ by binding to ___ receptors on ___

Answer 17

vasoconstriction

V1 on SMC

Question 18

bradykinin is generated from plasma protein ___ by ____

Answer 18

kininogen

kalikrein

Question 19

bradykinin mediates ___ by ___

Answer 19

vasodilation

endothelial NO generation

Question 20

regulation of vascular tone by circulating hormones (3)

Answer 20

RAS
ADH
Bradykinin

Question 21

AG2 binds to ___ on SMC resulting in ___

Answer 21

AT1

vasoconstriction

Question 22

______________ is a key regulator of arterial, arteriole, and venous/venule diameter

Answer 22

sympathetic nervous system

Question 23

perivascular sympathetic nerves arise from ______ and run across the ____ next to smooth muscle

Answer 23

postganglionic efferent axons

adventitia

Question 24

NE on a1 on SMC =

Answer 24

vasoconstriction

Question 25

NE on b1 on SMC =

Answer 25

vasodilation

Question 26

TXA2 binds to

Answer 26

TP

vasoconstrictor

Question 27

captopril is a

Answer 27

RAS inhibitor

Question 28

nifedipine (DHP) is a

Answer 28

Ca2+ antagonist that blocks SMC Ca2+ entry via L type channels

Question 29

prazosin is a

Answer 29

adrenoceptor antagonist that blocks NE action on VSMC

Question 30

nitroprusside is a

Answer 30

NO donor

Question 31

vasodilatory mech of nitroprusside

Answer 31

donates NO and activates cGMP signalling

Question 32

minoxidil action

Answer 32

open SMC K atp channels + prevent opening of VGCC

Question 33

K channel activators

Answer 33

minoxidil

Question 34

nicorandil action

Answer 34

open SMC K atp channels + prevent opening of VGCC + releases NO

Question 35

epoprostenol is a

Answer 35

AC activator = increases cAMP

Question 36

sildenafil is a

Answer 36

PDE inhibitor that prevents cGMP breakdown

Question 37

bosentan is a

Answer 37

ET receptor antagonist

Question 38

captopril and enalapril are

Answer 38

ACE inhibitors

Question 39

valsartan, losartan, and candesartan are

Answer 39

ARBs

Question 40

besides cleaving AG1 to AG2, ACE also cleaves

Answer 40

bradykinin = inactivates