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CMBM exam 3 > Eicosanoids > Flashcards

Eicosanoids Flashcards

1
Q

What is the major essential fatty acid that synthesizes arachidonic acid?

A

Linoleate

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2
Q

What is the source for all eicosanoids?

A

Arachidonic acid

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3
Q

How is arachidonic acid obtained to make eicosanoids?

A

Must be released from the phospholipids it is connected to by phospholipase A2 or C

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4
Q

What are eicosanoids?

A

Polysaturated fatty acids derived from the breakdown of phospholipids

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5
Q

What are eicosanoid biological functions?

A

Participate in inflammatory response and smooth muscle contraction
Short lived - act in autocrine or paracrine fashion

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6
Q

What are the enzymes are involved in eicosanoid synthesis?

A

Cyclo-oxygenase, lipoxygenase, cytochrome P450

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7
Q

Cyclo-oxygenase produces _____ and _____ from arachidonic acid.

A

Prostaglandins and thromboxanes

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8
Q

Lipoxygenase produces these three eicosanoids.

A

Leukotrienes, HETE, lipoxins

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9
Q

Cytochrome P450 produces _____ and _____.

A

diHETE and HETE

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10
Q

How many carbons does the ring on prostoglandin have?

A

5

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11
Q

How many carbons does the ring on thromboxane have?

A

6

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12
Q

What is the synthesis enzyme of prostoglandins and thromboxanes called?

A

Cyclooxygenase

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13
Q

What does cyclooxygenase do to the arachidonic acid?

A

Forms the 5 rings structure (PGG2)

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14
Q

What must PGG2 do to become stable?

A

Rapidly reduced by peroxidase to form PGH2

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15
Q

In vascular tissue, PGH2 becomes _____ via PGI synthase.

A

PGI2 (prostacyclin)

which modulates vascular tone and platelet aggregation

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16
Q

Platelets will convert PGH2 to _____ via TXA synthase.

A

TXA2

also modulates vascular tone and platelet aggregation

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17
Q

What are the two forms of cyclo-oxygenase (COX)?

A

COX-1: constitutively active, in most tissues, expressed in mature platelets
COX-2: induced form, normal low levels but up-regulated by cytokines and growth factor in inflamed tissues

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18
Q

What are COX 1 and 2 inhibited by?

A

Non-steroidal anti-inflammatory drugs (NSAIDS)

Aspirin, ibuprofen, acetaminophen

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19
Q

What does aspirin do to COX 1 and 2?

A

Transfers an acteyl group to enzyme, irreversibly inactivating it

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20
Q

Which NSAID are reversible inhibitors of COX?

A

Ibuprofen and acetaminophen

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21
Q

What are the COX-2 inhibitors that don’t cause GI problems or anti-platelet effects?

A

Celecoxib (Celebrex)

Rofecoxib (Vioxx) - not in market

22
Q

What do glucocorticoids do in terms of eicosanoid synthesis?

A

Inhibits inflammation by (PG synth) by blocking the action of phospholipase A (which changes a phospholipid into a arachidonic acid)

23
Q

What are leukotrienes?

A

Molecules synthesized by leukocytes which have a triene structure

24
Q

What are lipoxins?

A

Tri-hydroxy derivatives of arachidonic acid

25
Q

The lipoxygenase pathway starts with the conversion of _____ to _____ via lipoxygenase.

A

arachidonic acid, HPETEs

26
Q

What will the HPETE convert to spontaneously?

A

HETE

27
Q

How is lipotoxin formed from HETEs?

A

A series of reductions

28
Q

What does lipotoxin do?

A

Function to induce chemotaxis and stimulate superoxide anion production in leukocytes

29
Q

Epoxides are formed from certain forms of HETE called…

A

diHETEs (because they are diols)

30
Q

What pathway are epoxides formed thorugh?

A

Cytochrome p450

31
Q

What are epoxides implicated to do?

A

Not sure by probably ocular, vascular, endocrine and renal somethings and generally activate adenylyl cyclase, cAMP, or protein kinase A pathway

32
Q

Prostacyclin and Thromboxane have

A

antagonistic biological effects

33
Q

Functions of PGI, E, or D

A

increase vasodilation, cAMP,

decrease platelet aggregation, Leukocyte aggregation, lymphocyte migration, T cell proliferation

34
Q

Function of TXA2

A

Increases vasoconstriction, platelet aggregation, lymphocyte proliferation and broncho-constriction

35
Q

Low aspirin therapy to manage risk of thrombosis is given. What action of Eicosanoids does aspirin interfere with?

A

Platelet aggregation

36
Q

what are the functions of Lipoxins?

A

Stimulate leukocyte production of superoxides and anions

induce chemotaxis

37
Q

what are some functions of Leukotrienes?

A

increase vascular permeability, T cell proliferation, Leukocyte aggregation, Broncho constriction, release of pro-inflammatory cytokines such as IFN-y, IL-1 , IL-2

38
Q

Role of HETE and diHETEE

A

implicated in

Ocular, vascular, endocrine and renal systems

39
Q

PGE1 and 2

A

suppress gastric ulceration by preventing/stopping release of HCl acid from stomach mucous cells

40
Q

Can’t get it up? Try …

A

PGE1
just inject it into your penis
works via inducing vasodilation

41
Q

Mechanisms of action of eicosaniods via

A

activation of cAMP/PKA pathway

or increasing production of intracellular calcium

42
Q

Pro or anti inflammatory? - Leukotrienes

A

Pro

43
Q

Pro or anti inflammatory? Lipoxins

A

Pro

44
Q

Vasoconstrictive or vasodilator? Prostaglandins

A

PGF - vasoconstricts

PGI, E, D - Vasodilators

45
Q

Vasoconstrictor or vasodilator? Thromboxanes

A

Vasoconstrictor

46
Q

Induces Platelet aggregation?

A

Thromboxanes

47
Q

Broncho constrictor

A

PGF
TXA
LTC,LTD

48
Q

Increases vascular permeability?

A

Leukotrienes

49
Q

Stimulate uterine contraction, induce labor and control postpartum bleeding?

A

PGE2 and PGF2a

50
Q

Maintains a patent ductus arteriosus?

A

PGE1

51
Q

Analogs of PGI2 (Prostacyclin)

A

tx of primary pulmonary hypertension

CMBM exam 3 (24 decks)

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