L6. Autacoids Flashcards

1
Q

2 main categories of autacoids

A

histamine

eicosanoids

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2
Q

4 categories of eicosanoids

A
  1. prostanoids
  2. leukotrienes
  3. 12-HETE
  4. lipoxins
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3
Q

3 types of prostanoids

A
  1. Prostacyclins PGI2
  2. prostaglandins
  3. Thromboxane TXA2
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4
Q

3 types of prostaglandins

A

PGD2
PGF2a
PGE2

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5
Q

describe syntheiss of histamine

A

precursor L-histidine via L-histidine decarboxylase

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6
Q

which 2 cells store histamine

A

mast cells

basophils

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7
Q

2 times when histamine is release

A
  1. inflammation/allergic reaction

2. drugs

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8
Q

name 4 drugs which cause histamine release

A
  1. morphine
  2. radiocontrast media
  3. tubocurarine
  4. vancomycin
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9
Q

how does histamine release affect Ca2+?

A

increases cytosolic Ca2+

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10
Q

4 main histamine receptor

A

H1-H4

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11
Q

location of H1 receptor

A

smooth muscle

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12
Q

4 effect of histamine on H1 receptor

A
  1. vasodilation
  2. increased vascular perm
  3. contraction of smooth muscle
  4. itch and pain due to stimulation in nerve endings
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13
Q

2 location of H2 receptor

A

gastric parietal cells, heart

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14
Q

location of H3 receptor

A

presynaptic terminals

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15
Q

what is the triple response to histamine

A
  1. red spot
  2. brighter red flush/ flare
  3. wheal
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16
Q

what is the red spot caused by?

A

direct vasodilator effect

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17
Q

what is the flare caused by?

A

indirect vasodilation

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18
Q

what is the wheal caused by?

A

increased capillary permeability

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19
Q

2 pathophysiological roles of histamine

A
  1. type 1 hypersensitivity reactions

2. gastric acid secretion from gastric paritel cells

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20
Q

which receptor does histamine act on to produce hypersensitivity reaction

A

H1

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21
Q

which receptor does histamine act on to produce gastric acid secretion

A

H2

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22
Q

what 2 conditions are antihistamines only useful in treating

A

hayfever, urticaria

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23
Q

2 pathological conditions caused by excessive gastric acid secretion

A
  1. GORD - gastro-oesophageal reflux disease

2. peptic ulcers

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24
Q

2 examples of H1 receptor antagonists - which have a sedative effect

A

promethazine, chlorpheniramine

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25
Q

3 examples of H1 receptor antagonists - which dont have a sedative effect

A

cetrizine
fexofenadine
terfenadine

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26
Q

3 examples of H2 receptor antagonists

A
  1. cimetidine
  2. ranitidine
  3. famotidine
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27
Q

what are eicosanoids

A

lipid autacoids derived from PM phospholipids

28
Q

are eicosanoids stored? why?

A

no - they are formed from membrane phospholipids as needed

29
Q

which enzyme converts arachnidonate into its prostanoids?

A

cyclo-oxygenases

30
Q

what is released from the phospholipisd to form the eicosanoids

A

arachidonic acid

31
Q

which enzyme converts arachnidonate into leukotrienes?

A

5-lipoxygenases

32
Q

which enzyme forms PGE2?

A

reductase

33
Q

2 forms of cyclo-oxyegnases

A

COX 1 COX2

34
Q

where are COX1 enzyes?

A

most cells

35
Q

where are COX2 enzymes?

A

inflammatoyr clels

36
Q

how do NSAIDS work?

A

inhibit COX 1 and 2

37
Q

what are coxibs? how do thye work?

A

inhibit COX2

38
Q

advantages of COX2 over 1?

A

less GI SE

39
Q

where is TXA2 produced

A

platelets

40
Q

where is PGI2 produceed

A

vascular endothelium

41
Q

effects of PGD2 and PGI2 and PGE2

A

vasodilation

42
Q

effects of TXA2

A

vasoconstriction

43
Q

prostanoid responsible for myometrial contraction

A

PGF21

44
Q

where is PGE2 produced? in response to what?

A

hypothalamus; pyrogens

45
Q

5 clinical uses of prostanoid agonists

A
  1. medical abortion
  2. gastric cytoprotection
  3. impotence
  4. inhibit platelet aggregation
  5. glaucoma
46
Q

clincial use of prostanoid antagonists

A

anti-inflammatory

47
Q

3 examples of NSAIDS

A

aspirin, ibuprofen , naproxen

48
Q

2 examples of Coxibs

A

celecoxib, etoricoxib

49
Q

can pcm be used as an anti-inflammatory? explain?

A

no - only affects COX in brain not periphery - only has anti-pyretic and analgesic effects

50
Q

4 clinical uses of NSAIDS

A
  1. anti-inflammatory
  2. analgesic
  3. antipyretic
  4. prophylaxis on MI
51
Q

why should only a low aspirin dose be used as prophlyaxis against MI?

A

low doses selectively inhibit TXA2 - without inhibiting PGI2

52
Q

what leukotrine is produced by neutrophils

A

LTB4

53
Q

which leukotriene modulates renal function

A

12-HETE

54
Q

function of lipoxins A and B

A

oppose actions of LTB4

55
Q

function of LTB4

A

chemoattractant for inflammatory cells

56
Q

2 function of cysteinul-leukotrienes

A

bronchoconstrictors

increase vascular permeability

57
Q

clinical use of Cys-L antagonists - give 1 example of a drug

A

asthma - montelukast

58
Q

does histamine cause vaso constriction or vasodilation

A

vasodilation

59
Q

T/F : Arachidonic acid is produced by the action of cyclooxygenase enzyme on the membrane phospholipids.

A

false

60
Q

which prostanoid protects gastric mucosa?

A

PGE2

61
Q

Cysteinylleukotrienes are potent ____________

A

bronchoconstricor

62
Q

Allergic reactions which is called Type I hypersensitivity reactions result from the production of

A

IgE

63
Q

Prostanoids and leukotrienes are both formed from

A

arachidonic acid

64
Q

example of irreverisble COX inhibitor drug

A

aspirin

65
Q

does pcm have an anti-inflammatoyr effct?

A

no

66
Q

what category of drugs does loratadine belong to

A

antihistamine

67
Q

why do NSAIDS have an anti-inflammtory effect

A

they inhibit prostaglandins