Autacoids

Question 1

Define autacoid

Answer 1

autacoid are biological factors that act like local hormones; that is they have a paracrine effect. Unlike hormones autacoids are produced in minute quantities and have local, brief effects. Notable human autacoids include eicosanoids, angiotensin, nitric oxide, kinins, histamine, serotonin, and endothelins

Question 2

What are eicosanoids?

Answer 2

Eicosanoids are signaling molecules derived from omega-3 and Omega 6 fatty acids, including arachidonic acid. They include prostaglandins, thromboxanes, leukotrienes, and lipoxins. Eicosanoids are not stored but rather are produced on demand

Question 3

How are prostanoids related to eicosanoids?

Answer 3

Prostanoids are metabolic derivatives of arachidonic acid; therefore, prostanoids are a category of eicosanoids. Cyclooxygenase acts on arachidonic acid to produce PGH 2. Three types of prostanoids are then derived from PGH 2: prostaglandins, prostacyclins, and thromboxanes.

Question 4

Arachidonic acid and Omega 6 fatty acid is liberated from membrane phospholipids by the action of what enzyme?

Answer 4

phospholipids A2 acts upon membrane phospholipids to release arachidonic acid

Question 5

Which prostanoid is implicated in the rebound prothrombotic state often seen following discontinuation of antiplatelet therapy?

Answer 5

an increased thromboxane 2 activity is seen during the rebound

Question 6

Name two prostanoids that are potent inhibitors of platelet aggregation and thus promote and maintain an anti thrombotic state in vessels?

Answer 6

prostacyclin and PGD 2, along with nitric oxide and other factors

Question 7

which prostanoid produces vascular smooth muscle contraction and is thus a potent vasoconstrictor?

Answer 7

thromboxane A2 produces contraction of vascular smooth muscle and is a potent vasoconstrictor

Question 8

List two prostanoids that cause bronchodilation/constriction

Answer 8

pge 2 and pgi 2 are bronchodilators

PGF 2A, PGD 2, and TxA cause bronchoconstriction

Question 9

How are leukotrienes related to eicosanoids?

Answer 9

leukotrienes are metabolic derivatives of arachidonic acid, therefore leukotrienes are a category of eicosanoids

Question 10

What action do leukotrienes have on the lungs? What cells synthesize and release leukotrienes?

Answer 10

Activated mast cells and basophils synthesize and release leukotrienes. Leukotrienes evoke inflammatory responses in the lungs, including intense bronchoconstriction and increased pulmonary vascular permeability.

Question 11

What is another name for the mixture of leukotrienes C4, D4, and E4?

Answer 11

slow reacting substance of anaphylaxis

Question 12

Which herbal supplement is a potent inhibitor of thromboxane synthesis and thus has synergistic effects with other antiplatelet agents?

Answer 12

Ginger