13: Nitric oxide and H2S

Question 1

why is NO highly reactive

Answer 1

it’s a free radical

Question 2

what forms NO

Answer 2

L arg and O2

Question 3

what is EDRG

Answer 3

endothelial derived relaxing factor (NO)

Question 4

vasodilation by ACh, bradykinin, histamine, ATP due to

Answer 4

EDRF

Question 5

3 isoforms of NO

Answer 5

eNOS
nNOS
iNOS

Question 6

where are eNOS found

Answer 6

endothelial cells

Question 7

where are nNOS ofund

Answer 7

neurons

Question 8

where are iNOS found

Answer 8

macrophages

Question 9

which isoform of NOS is inducible

Answer 9

iNOS

Question 10

which isoform of NOS produces the least NO

Answer 10

eNOS and nNOS

Question 11

the rate of production of NO is determined by

Answer 11

the enzyme rather than the amount of substrate

Question 12

NOS homodimers are inactive or active

Answer 12

active

Question 13

what facilitates dimer formation for NOS

Answer 13

TH4 and heme

Question 14

what group do NOS belong to

Answer 14

oxidoreductases

Question 15

bound Ca2+ calmodulin facilitates transfer of electrons from

Answer 15

NADPH to flavin to heme

Question 16

what does eNOS and nNOS require as cofactors that iNOS doesn’t

Answer 16

Ca2+/ calmodulin

Question 17

cGMP independent effects

Answer 17

bind other heme containing enzymes
S-nitrosylation of thiol groups
deamination of DNA bases

Question 18

what can cGMP affect

Answer 18

ion channels
protein kinases (PKG)
phosphodiesterases (PDE)

Question 19

what is cGMP broken down by? into what?

Answer 19

PDE5 into 5’GMP

Question 20

3 major pathways for NO inactivation

Answer 20

binding hemoglobin
formation of nitrate and nitrite
formation of peroxynitrite

Question 21

eNOS is regulated by

Answer 21

phosphorylation

Question 22

what can eNOS be activated by

Answer 22

Ca-calmodulin

sheer stress - Akt

Question 23

which NOS inhibits platelet adhesion and aggregation + tonically active in resistance vessels

Answer 23

eNOS

Question 24

what decerases periperal vascular resistance and bp

Answer 24

eNOS

Question 25

what leads to NO production by nNOS

Answer 25

NMDA receptor activation

Question 26

NO is a ___ in the CNS important for_____

Answer 26

NT | learning and memory formation

Question 27

NO is a ___ in the PNS

Answer 27

NANC NT

Question 28

what does NO do in the PNS

Answer 28

neurogenic vasodilation GI, resp, genitourinary functions autonomic innervation of SM

Question 29

what regulates. influences neuroendocrine function

Answer 29

NO from nNOS

Question 30

iNOS is regulated by

Answer 30

transcription

Question 31

iNOS is _______ host defence

Answer 31

nonspecific

Question 32

what is expressed in response to endotoxins, IL1, IFN, TNF

Answer 32

iNOS

Question 33

what is activated against bacteria, viruses, fungi, protozoa, parasites, tumor cells

Answer 33

iNOS

Question 34

what does iNOS cause

Answer 34

nitrosylation of NA binds heme enzymes binds mitochondrial enzymes responsible for respiration

Question 35

what inhibits iNOS

Answer 35

glucocorticoids

Question 36

excess production of NO results in

Answer 36

hypotension excitotoxicity inflammatory conditions- no drugs for this

Question 37

inadequate NO results in

Answer 37

atherogenesis, thrombosis, hypertrophic pyloric stenosis, erectile dysfunction, pulmonary hypertension in newborn

Question 38

nitroglycerin treats

Answer 38

angina

Question 39

nitroprusside treats

Answer 39

hypertensive crisis

Question 40

nebivolol effect

Answer 40

increases NOS

Question 41

statins effect

Answer 41

increase in iNOS and decrease cholesterol

Question 42

PDE5 inhibitors do what

Answer 42

block breakdown of cAMP

Question 43

sidenafil and tadarafil do what

Answer 43

ehnance actions of NO

Question 44

what to give to newborn with pulmonary hypertension

Answer 44

inhaled NO

Question 45

other gases as chemical mediators

Answer 45

CO and H2S

Question 46

how is CO produced

Answer 46

endogenous by heme oxygenase

Question 47

effect of CO and H2S at low conc

Answer 47

both are vasodilators | H2S has antiinflammatory effects

Question 48

H2S is produced from __ by

Answer 48

cysteine | cystathionine gamma lyase or cystathionine beta synthase

Question 49

H2S is excreted as

Answer 49

thiosulfate, sulfite/ sulfate in urine