Lecture 11: Arachidonic Acid Pathway Flashcards Preview

Gastrointestinal and Liver > Lecture 11: Arachidonic Acid Pathway > Flashcards

Flashcards in Lecture 11: Arachidonic Acid Pathway Deck (30):
1

Eicosanoids are products of oxygenation of...

Polyunsaturated long-chain fatty acids, including arachidonic acid (most abundant eicosanoid precursor), released from membrane

2

Products of the COX pathway

Prostaglandins, prostacyclin, thromboxane

3

Effects of prostaglandins on vascular SM

Vasoconstrictors (TXA2 and PGF2alpha) AND vasodilators (PGI2 and PGE2)

4

PGI2

Vasodilation and inhibition of SM proliferation

5

TXA2

Vasoconstriction and SM mitogen

6

COX1 and COX2

COX1 = found in all tissues, especially in GI; COX2 = upregulated in kidney, GI, CNS, endothelium

7

Contraction of longitudinal, circular muscles in GI tract

PGF2 (also causes vasoconstriction)

8

Relaxation of circular muscles

PGE2 (also causes vasodilation)

9

Contraction of respiratory SM

TXA2, PGF2alpha

10

Relaxation of respiratory SM

PGE2, PGI2

11

Inhibit platelet aggregation

Higher concentration of PGE2, PGD2, PGI2

12

TXA2 and platelets

Directly enhances platelet aggregation and augments other platelet agonists (thrombin)

13

Vasodilation in kidney: mediators, where, and effect on GFR

Most in afferent arteriole, PGE2 and PGI2, increase GFR (GOOD)

14

PGE2 and PGI2 stimulates ________ release. Results in?

Renin --> increased AII --> constricted efferent arteriole --> increased hydrostatic pressure --> increase GFR (GOOD)

15

TXA2 and the kidney

Renal constriction (mostly afferent) --> decreased GFR

16

Net effect of eiconsanoids on GFR is to ___________ GFR

Increase (TXA2 not as strong)

17

PGE2 and PGI2 effect on Na+ and water

Increases Na+ excretion (via decreased Na+ resaobsorption) and increases water excretion (via attenuated ADH)

18

PGE2 and PGI2 effect on blood pressure via excretion

Maintains a low blood pressure

19

What is the net of effect of prostaglandins on BP? What are the two things behind this balance?

Decrease BP: PGE2 and PGI2 --> balance b/t Na+ and H2O excretion (decrease BP) VS increase in renin (increase BP)

20

What prostaglandins increase body temperature? Why does this make sense?

PGE2, PGF2alpha, PGI2; NSAIDs are FEVER REDUCERS

21

Effects of PGE on neurotransmission

PGE inhibit release of NE from sympa postganglionic nerve endings, leading to LESS VASOCONSTRICTION

22

Two reasons that COX inhibition causes vasoconstiriction

Leads to NE release AND inhibit synthesis of vasodilators (PGE2 and PGI2)

23

Peripheral nerve endings are sensitized to pain by...How?

PGE2 and PGI2; increased membrane excitability

24

Prostaglandins effects on CNS pain modulation (3)

Increase excitability of spinal dorsal horn neurons, augment pain intensity, widen pain perception area

25

Effects of PGE2 and PGI2 on inflammation

Increase vascular permeability and leukocyte infiltration

26

Prostaglandins in the eye...

PGE and PGF derivatives lower intra ocular pressure (Latanoprost)

27

LOX pathway creates what? What do these do (main, opposing actions)?

HETEs, leukotrienes, lipoxins; Leukotrienes: Potent chemoattractants for eos and T-cells --> inflammation; Lipoxins: activate macrophages, inhibit eos, lymphocytes

28

Leukotrienes are a product of the LOX pathway. Importance for airways?

Bronchoconstrictors --> bronchoconstriction, increased permeability, and increased mucus secretion

29

NSAIDs and airways

10% of patients taking NSAIDs have bronchospasm likely from shifting arachidonate metabolism from COX to the leukotriene arm

30

Cytochrome P450/EET and LOX pathways on the heart

LOX --> proliferation of SM In vascular, decreased coronary blood flow, decreased contractility; EET --> vasodilation of cardiac vessels