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Eicosanoids and Fatty Acid Derivatives
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Eicosanoids and Fatty Acid Derivatives

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Questions and Answers

What is the primary function of COX-1 in the synthesis of prostaglandins?

  • Involvement in inflammatory reactions
  • Regulation of platelet aggregation only
  • Facilitation of fever and pain sensation
  • Synthesis of protective prostaglandins (correct)

    • Which cyclooxygenase isoform is primarily associated with the synthesis of undesirable prostaglandins?

  • COX-3
  • All COX isoforms
  • COX-1
  • COX-2 (correct)

    • What distinguishes COX-3 from other cyclooxygenase isoforms?

  • It converts arachidonic acid into thromboxanes
  • It is exclusively found in the brain (correct)
  • It is the most abundant isoform in platelets
  • It primarily regulates stomach acid secretion

    • Which compound acts as the potent endogenous stimulator of platelet aggregation?

    <p>TXA2</p> Signup and view all the answers

    Which prostaglandin is NOT produced by COX-1 activity?

    <p>PGF2α</p> Signup and view all the answers

    What role does acetaminophen play in relation to COX-3?

    <p>It selectively inhibits COX-3, reducing fever and pain sensation</p> Signup and view all the answers

    Which of the following is a feature of thromboxanes (TXs)?

    <p>They play a crucial role in platelet aggregation</p> Signup and view all the answers

    What is a characteristic of COX-2 activity?

    <p>Inducible during inflammatory responses</p> Signup and view all the answers

    What is the primary role of PGE1 in neonates and infants?

    <p>To maintain ductus arteriosus patency for oxygenation</p> Signup and view all the answers

    Which of the following conditions can PGE2 be used to treat?

    <p>Induction of labor near full term</p> Signup and view all the answers

    What is the mechanism of action of Mesoprostol in patients taking NSAIDs?

    <p>It prevents gastric ulceration</p> Signup and view all the answers

    Which prostaglandin is primarily used to treat open-angle glaucoma?

    <p>PGF2α</p> Signup and view all the answers

    What is a key function of PGI2 (Prostacyclin)?

    <p>Inhibiting platelet aggregation</p> Signup and view all the answers

    What distinguishes newer NSAIDs like celecoxib from classical NSAIDs?

    <p>They selectively inhibit COX-2</p> Signup and view all the answers

    Which class of drugs inhibits the synthesis of all eicosanoids by blocking phospholipase A2?

    <p>Corticosteroids</p> Signup and view all the answers

    What effect does PGF2α have when used with mifepristone?

    <p>Enhance uterine contractions for therapeutic abortion</p> Signup and view all the answers

    What are the main types of leukotrienes?

    <p>LTB4, LTC4, LTD4, LTE4</p> Signup and view all the answers

    Which leukotriene is known for its powerful bronchoconstrictor and chemotactic properties?

    <p>LTB4</p> Signup and view all the answers

    Which of the following eicosanoids promotes vasodilation?

    <p>PGE1</p> Signup and view all the answers

    What is the action of PGE1 in the treatment of erectile dysfunction?

    <p>Vasodilation of vascular smooth muscle</p> Signup and view all the answers

    Which eicosanoid primarily causes contraction of the non-pregnant uterus?

    <p>PGF2α</p> Signup and view all the answers

    What is the effect of LTB4 on platelet aggregation?

    <p>Decreases aggregation</p> Signup and view all the answers

    What role does PGE1 play for infants with congenital cyanotic heart diseases?

    <p>Maintains ductus arteriosus patency</p> Signup and view all the answers

    Which eicosanoid is associated with chemotaxis?

    <p>LTB4</p> Signup and view all the answers

    COX-1 is primarily involved in the synthesis of undesirable prostaglandins.

    <p>False</p> Signup and view all the answers

    Thromboxane A2 is the inactive form of thromboxanes.

    <p>False</p> Signup and view all the answers

    The central isoform of cyclooxygenase is known as COX-3 and is selectively inhibited by analgesic drugs.

    <p>True</p> Signup and view all the answers

    Prostaglandins are derived from fatty acids that contain more than 20 carbons.

    <p>False</p> Signup and view all the answers

    The action of cyclooxygenase enzymes results in the synthesis of both thromboxanes and leukotrienes.

    <p>False</p> Signup and view all the answers

    Prostaglandin E2 (PGE2) plays a role in protecting the stomach from hydrochloric acid.

    <p>True</p> Signup and view all the answers

    COX-2 is constitutively expressed in platelets.

    <p>False</p> Signup and view all the answers

    Both COX-1 and COX-2 isoforms are involved in the synthesis of thromboxanes.

    <p>False</p> Signup and view all the answers

    Mesoprostol is approved to treat excessive gastrointestinal bleeding in patients taking NSAIDs.

    <p>False</p> Signup and view all the answers

    PGI2, also known as Prostacyclin, can inhibit platelet aggregation.

    <p>True</p> Signup and view all the answers

    PGE2 is primarily indicated for the treatment of open-angle glaucoma by reducing intraocular pressure.

    <p>False</p> Signup and view all the answers

    Corticosteroids inhibit the synthesis of certain eicosanoids by blocking cyclooxygenase enzymes.

    <p>False</p> Signup and view all the answers

    The action of PGF2α includes the induction of labor and therapeutic abortion.

    <p>True</p> Signup and view all the answers

    Celecoxib selectively inhibits COX-1 while sparing COX-2 in its action.

    <p>False</p> Signup and view all the answers

    Thromboxanes and leukotrienes currently have significant clinical applications.

    <p>False</p> Signup and view all the answers

    Induction of labor can be achieved using both Dinoprostone and Enzaprost.

    <p>True</p> Signup and view all the answers

    Leukotrienes are derived from arachidonic acid by the action of cyclooxygenase enzymes.

    <p>False</p> Signup and view all the answers

    LTB4 is a powerful bronchoconstrictor and chemotactic for leukocytes.

    <p>True</p> Signup and view all the answers

    PGE1 is used exclusively to maintain patency of the ductus arteriosus in infants.

    <p>False</p> Signup and view all the answers

    The therapeutic use of PGF2α includes promoting vasodilation in smooth muscle.

    <p>False</p> Signup and view all the answers

    The slow-reacting substance of anaphylaxis (SRS-A) is a mixture of LTC4, LTD4, and LTE4.

    <p>True</p> Signup and view all the answers

    Prostaglandins act on cell surface G-protein coupled receptors classified as FP, EP, DP1, and DP2.

    <p>True</p> Signup and view all the answers

    TXA2 induces platelet aggregation while PGE2 decreases it.

    <p>False</p> Signup and view all the answers

    LTB4 is known to promote edema formation.

    <p>True</p> Signup and view all the answers

    What enzyme is involved in the synthesis of leukotrienes from arachidonic acid?

    <p>Lipooxygenase.</p> Signup and view all the answers

    Which leukotrienes constitute the slow-reacting substance of anaphylaxis (SRS-A)?

    <p>LTC4, LTD4, and LTE4.</p> Signup and view all the answers

    What are the effects of LTB4 on leukocytes?

    <p>It acts as a chemotactic agent, attracting leukocytes to sites of inflammation.</p> Signup and view all the answers

    Describe the vasodilatory effects of PGE2 and PGI2.

    <p>PGE2 causes vasodilation, while PGI2 (Prostacyclin) also promotes vasodilation and inhibits platelet aggregation.</p> Signup and view all the answers

    How does PGE1 function in the treatment of erectile dysfunction?

    <p>It induces vasodilation of the vascular smooth muscle in the corpus cavernosum.</p> Signup and view all the answers

    What is the impact of TXA2 on platelet aggregation?

    <p>TXA2 promotes platelet aggregation and vasoconstriction.</p> Signup and view all the answers

    Which eicosanoid is primarily responsible for the contraction of the pregnant uterus?

    <p>PGF2α.</p> Signup and view all the answers

    What is the primary therapeutic use of PGE1 in neonates?

    <p>To maintain patency of the ductus arteriosus in congenital cyanotic heart conditions.</p> Signup and view all the answers

    Explain the role of PGE1 in the management of ductus arteriosus in neonates.

    <p>PGE1 maintains ductus arteriosus patency, ensuring additional oxygenation of blood until surgical correction.</p> Signup and view all the answers

    How do corticosteroids affect eicosanoid synthesis?

    <p>Corticosteroids inhibit phospholipase A2, thus blocking the synthesis of all eicosanoid families.</p> Signup and view all the answers

    Compare the mechanisms of action between classical NSAIDs and COX-2 selective inhibitors like celecoxib.

    <p>Classical NSAIDs inhibit both COX-1 and COX-2 non-selectively, while COX-2 inhibitors selectively block COX-2 activity.</p> Signup and view all the answers

    Discuss the clinical applications of PGI2 (Prostacyclin).

    <p>PGI2 is used to inhibit platelet aggregation during surgeries and to treat pulmonary hypertension.</p> Signup and view all the answers

    What is the significance of combining PGF2α with mifepristone in therapeutic abortion?

    <p>Combining PGF2α with mifepristone enhances uterine contractions, making the procedure more effective.</p> Signup and view all the answers

    Analyze the use of Mesoprostol in patients with NSAID-induced gastric ulcers.

    <p>Mesoprostol protects the gastric lining by enhancing mucus secretion and reducing acid production.</p> Signup and view all the answers

    Describe the function of PGF2α in obstetrics.

    <p>PGF2α induces labor and is used for therapeutic abortion, facilitating uterine contractions.</p> Signup and view all the answers

    What is the role of PGE2 in the treatment of open-angle glaucoma?

    <p>PGE2 promotes uveoscleral outflow of aqueous humor, thereby reducing intraocular pressure.</p> Signup and view all the answers

    What are the main functions of COX-1 derived prostaglandins in physiological processes?

    <p>They provide protection to the stomach lining, regulate renal blood flow, and inhibit platelet aggregation.</p> Signup and view all the answers

    Describe the role of COX-2 in the context of inflammatory responses.

    <p>COX-2 is involved in the synthesis of pathogenic prostaglandins that mediate inflammation and bronchoconstriction.</p> Signup and view all the answers

    What distinguishes thromboxane A2 (TXA2) from its inactive form TXB2?

    <p>TXA2 is a potent stimulant of platelet aggregation, while TXB2 is inactive and does not promote aggregation.</p> Signup and view all the answers

    How does the presence of COX-3 in the central nervous system affect pain sensation?

    <p>COX-3 is implicated in synthesizing prostaglandins that mediate fever and pain, selectively inhibited by analgesic drugs.</p> Signup and view all the answers

    Explain the significance of prostaglandins in gastric protection and renal function.

    <p>Prostaglandins maintain mucosal integrity in the stomach and regulate blood flow in the kidneys, which are vital for preventing ulcers and ensuring adequate filtration.</p> Signup and view all the answers

    What is the impact of acetaminophen on COX-3 activity?

    <p>Acetaminophen selectively inhibits COX-3, leading to reduced fever and pain sensations.</p> Signup and view all the answers

    In what way do the isoforms of cyclooxygenase (COX) differ in their physiological and pathological roles?

    <p>COX-1 is primarily responsible for protective functions, while COX-2 is induced during inflammatory processes.</p> Signup and view all the answers

    What relationship do eicosanoids have with arachidonic acid metabolism?

    <p>Eicosanoids are derived from the metabolism of arachidonic acid by cyclooxygenase enzymes, playing crucial roles in inflammation and physiological regulation.</p> Signup and view all the answers

    Prostaglandins (PGs) are derived from arachidonic acid by the action of ______ enzyme.

    <p>cyclooxygenase</p> Signup and view all the answers

    COX-1 is involved in the synthesis of protective prostaglandins responsible for the ______ of the stomach from hydrochloric acid.

    <p>protection</p> Signup and view all the answers

    Thromboxane A2 (TXA2) is the most potent endogenous stimulator of ______ aggregation.

    <p>platelet</p> Signup and view all the answers

    COX-2 is primarily involved in the synthesis of undesirable prostaglandins implicated in ______ reactions.

    <p>inflammatory</p> Signup and view all the answers

    COX-3 is a variant of COX-2 that is primarily found in the ______.

    <p>brain</p> Signup and view all the answers

    Dipyrones and acetaminophen selectively inhibit ______ to reduce fever and pain.

    <p>COX-3</p> Signup and view all the answers

    Thromboxanes are synthesized in high concentration in ______.

    <p>platelets</p> Signup and view all the answers

    The active form of thromboxanes is known as ______ A2.

    <p>TXA2</p> Signup and view all the answers

    Leukotrienes are derived from arachidonic acid by the action of ________ enzyme.

    <p>lipoxygenase</p> Signup and view all the answers

    A mixture of LTC4, LTD4, and LTE4 is termed the slow-reacting substance of ________.

    <p>anaphylaxis</p> Signup and view all the answers

    LTB4 is a powerful ________ and chemotactic for leukocytes.

    <p>bronchoconstrictor</p> Signup and view all the answers

    PGE1 (Alprostadil) is used as a treatment for erectile dysfunction by producing ________ of the vascular smooth muscle.

    <p>vasodilation</p> Signup and view all the answers

    Different eicosanoids act on cell surface ________-protein coupled receptors.

    <p>G</p> Signup and view all the answers

    In pregnant women, the action of prostaglandins includes ________ of the uterus.

    <p>contraction</p> Signup and view all the answers

    The pharmacological actions of eicosanoids include promoting ________ in blood vessels.

    <p>vasodilation</p> Signup and view all the answers

    The therapeutic uses of PGE1 include maintaining patency of the ________ arteriosus in infants.

    <p>ductus</p> Signup and view all the answers

    The ductus arteriosus is necessary for additional oxygenation until surgical correction is undertaken in neonates and ______.

    <p>infants</p> Signup and view all the answers

    Mesoprostol is approved for use in patients taking high doses of NSAIDs to prevent gastric ______.

    <p>ulceration</p> Signup and view all the answers

    Dinoprostone is used for the induction of labor near full term and is a form of ______.

    <p>PGE2</p> Signup and view all the answers

    Prostacyclin, or ______, is used to inhibit platelet aggregation during certain medical procedures.

    <p>PGI2</p> Signup and view all the answers

    Therapeutic abortion can involve the use of PGF2α as vaginal ______.

    <p>suppositories</p> Signup and view all the answers

    Corticosteroids inhibit the synthesis of all the eicosanoids family by blocking the enzyme ______ A2.

    <p>phospholipase</p> Signup and view all the answers

    Newer NSAIDs, like celecoxib, selectively inhibit ______-2.

    <p>COX</p> Signup and view all the answers

    Induction of labor can also be achieved using ______ in addition to Dinoprostone.

    <p>Enzaprost</p> Signup and view all the answers

    Match the following eicosanoids with their primary function:

    <p>Prostaglandin E2 (PGE2) = Protection of the stomach lining Thromboxane A2 (TXA2) = Platelet aggregation Prostaglandin F2α (PGF2α) = Induction of labor Prostacyclin (PGI2) = Inhibition of platelet aggregation</p> Signup and view all the answers

    Match the cyclooxygenase isoforms with their characteristics:

    <p>COX-1 = Constitutive expression and physiological role COX-2 = Inducible expression and pathological role COX-3 = Central nervous system action COX-1 and COX-2 = Involved in synthesis of thromboxanes</p> Signup and view all the answers

    Match the following prostaglandins with their associated effects:

    <p>PGE2 = Regulation of renal blood flow PGI2 = Vasodilation PGF2α = Bronchoconstriction TXA2 = Vasoconstriction</p> Signup and view all the answers

    Match the action of acetaminophen with the associated cyclooxygenase isoform:

    <p>Inhibition of COX-1 = Reduction of stomach protection Inhibition of COX-2 = Reduction of inflammation Inhibition of COX-3 = Pain relief and fever reduction Selective inhibition = Does not affect TXA2 synthesis</p> Signup and view all the answers

    Match the effects of thromboxanes with their impact:

    <p>TXA2 = Acts as a vasoconstrictor TXB2 = Role in thrombosis prevention</p> Signup and view all the answers

    Match the types of eicosanoids with their categories:

    <p>Prostaglandins = Derived from arachidonic acid Thromboxanes = Produced in platelets Leukotrienes = Involved in inflammatory responses All of the above = Products of cyclooxygenase action</p> Signup and view all the answers

    Match the conditions with the prostaglandins that may treat them:

    <p>PGE2 = Open-angle glaucoma PGF2α = Labor induction PGI2 = Pulmonary hypertension TXA2 = Thrombotic disorders</p> Signup and view all the answers

    Match the features of eicosanoids with their definitions:

    <p>Eicosanoids = 25 carbon fatty acid derivatives Prostaglandins = Act on G-protein coupled receptors Thromboxanes = Stimulate platelet aggregation Leukotrienes = Mediate allergic responses</p> Signup and view all the answers

    Match the eicosanoids with their primary effects:

    <p>PGE1 = Vasodilation of the vascular smooth muscle TXA2 = Platelet aggregation LTB4 = Bronchoconstriction and chemotaxis PGF2α = Uterine contraction</p> Signup and view all the answers

    Match the types of leukotrienes with their corresponding codes:

    <p>LTB4 = Chemotactic for leukocytes LTC4 = Part of the slow-reacting substance of anaphylaxis (SRS-A) LTD4 = Potent bronchoconstrictor LTE4 = Associated with inflammatory responses</p> Signup and view all the answers

    Match the therapeutic uses of prostaglandins with their corresponding drug:

    <p>PGE1 = Urethral inserts for erectile dysfunction PGF2α = Induction of labor PGE2 = Cytoprotection in the stomach PGI2 = Inhibiting platelet aggregation</p> Signup and view all the answers

    Match the effects of eicosanoids on blood vessels:

    <p>PGE1 = Vasodilation (VD) PGF2α = Vasoconstriction (VC) TXA2 = Vasoconstriction (VC) PGI2 = Vasodilation (VD)</p> Signup and view all the answers

    Match the action of leukotrienes with their specific effects:

    <p>LTB4 = Severe bronchoconstriction LTC4 = Mediates inflammation LTD4 = Asthmatic response LTE4 = Involved in allergic reactions</p> Signup and view all the answers

    Match the prostaglandin with its primary therapeutic use:

    <p>PGE1 = Maintain patency of the ductus arteriosus PGE2 = Induction of labor PGI2 = Inhibit platelet aggregation PGF2α = Therapeutic abortion</p> Signup and view all the answers

    Match the eicosanoids with their vasodilatory or vasoconstrictory effects:

    <p>PGE2 = Vasodilation (VD) TXA2 = Vasoconstriction (VC) PGI2 = Vasodilation (VD) PGF2α = Vasoconstriction (VC)</p> Signup and view all the answers

    Match the drug to its mechanism of action:

    <p>Mesoprostol = Prevent gastric ulceration in NSAID users Dinoprostone = Induce labor near full term Enzaprost = Induction of labor Latanoprost = Treat open-angle glaucoma</p> Signup and view all the answers

    Match the eicosanoids with their regulatory roles:

    <p>PGF2α = Uterine contraction during pregnancy PGE1 = Maintaining ductus arteriosus patency TXA2 = Stimulates vasoconstriction PGI2 = Platelet inhibition</p> Signup and view all the answers

    Match the condition with the relevant prostaglandin:

    <p>Mesoprostol = Gastric ulcer prevention PGI2 = Pulmonary hypertension PGF2α = Induction of labor PGE1 = Neonatal ductus arteriosus patency</p> Signup and view all the answers

    Match the receptors with the eicosanoid they primarily bind to:

    <p>DP1-2 = Prostaglandins EP1-4 = Prostaglandins FP = Prostaglandins CXCR1 = Leukotrienes (not listed but plausible with title)</p> Signup and view all the answers

    Match the class of drug with its site of action:

    <p>Corticosteroids = Inhibit phospholipase A2 NSAIDs = Inhibit cyclooxygenase enzyme Newer NSAIDs = Selective COX-2 inhibition Classical NSAIDs = Non-selective COX inhibition</p> Signup and view all the answers

    Match the eicosanoid with its physiological effect:

    <p>PGI2 = Inhibit thrombosis TXA2 = Promote platelet aggregation PGE2 = Decreases gastric acid secretion PGF2α = Enhances uterine contractions</p> Signup and view all the answers

    Match the indication with the specific prostaglandin:

    <p>Dinoprostone = Labor induction Latanoprost = Open-angle glaucoma treatment PGI2 = Peripheral vascular disease treatment PGE2 = Cervical ripening</p> Signup and view all the answers

    Match the prostaglandin with its associated complication or condition:

    <p>PGE1 = Congenital cyanotic heart disease PGF2α = Therapeutic abortion PGE2 = Increased uterine contractions PGI2 = Cardiopulmonary bypass surgery</p> Signup and view all the answers

    Match the clinical use with the drug mechanism:

    <p>Mifepristone = Anti-progesterone for abortion Mesoprostol = Gastric protection with NSAIDs Prostacyclin = Inhibit platelet aggregation PGE2 = Cervical preparation for labor</p> Signup and view all the answers

    Study Notes

    Eicosanoids Overview

    • Eicosanoids are fatty acid derivatives derived from arachidonic acid (20 carbons).
    • Main types include prostaglandins (PGs), thromboxanes (TXs), and leukotrienes (LTs).

    Prostaglandins (PGs)

    • Derived from arachidonic acid by cyclooxygenase (COX) enzymes.
    • Three isoforms of COX:
      • COX-1: Physiological role; synthesizes protective PGs (e.g., PGE2, PGI2) critical for stomach protection against HCl, renal blood flow regulation, and platelet aggregation inhibition.
      • COX-2: Inducible and involved in synthesizing undesirable PGs (e.g., PGF2α, PGD2) that contribute to inflammation and bronchoconstriction.
      • COX-3: A variant found in the brain, involved in fever and pain sensation; selectively inhibited by analgesics like acetaminophen.

    Thromboxanes (TXs)

    • Products of cyclooxygenase, primarily synthesized in platelets.
    • Two forms:
      • TXA2: Active form and potent stimulator of platelet aggregation.
      • TXB2: Inactive form.

    Leukotrienes (LTs)

    • Derived from arachidonic acid by lipoxygenase enzymes.
    • Main types: LTB4, LTC4, LTD4, and LTE4.
    • SRS-A (Slow-reacting substance of anaphylaxis) is a mixture of LTC4, LTD4, and LTE4, released during inflammatory response.
    • LTB4 is a strong bronchoconstrictor and a potent chemotactic factor for leukocytes.

    Pharmacological Actions of Eicosanoids

    • Eicosanoids interact with G-protein coupled receptors (DP1-2, EP1-4, FP, etc.).
    • Effects of various eicosanoids:
      • PGE1, PGE2: Vasodilation (VD), increased renal blood flow (RBF), bronchial relaxation.
      • PGI2: VD and anti-aggregation effects on platelets.
      • PGF2α: Vasoconstriction (VC), uterine contraction (both during pregnancy and non-pregnancy).
      • TXA2: Promotes platelet aggregation and VC.
      • LTB4: Contributes to edema and severe bronchoconstriction.

    Therapeutic Uses of Prostaglandins

    • PGE1 (Alprostadil):
      • Urethral inserts for erectile dysfunction; causes VD in corpus cavernosum.
      • Maintains ductus arteriosus patency in congenital heart diseases.
      • Treatment of peptic ulcers with Mesoprostol to prevent ulceration during NSAID use.
    • PGE2:
      • Induces labor (Dinoprostone) and treats peripheral vascular disease.
    • PGI2 (Prostacycline):
      • Inhibits platelet aggregation, used during surgery, dialysis, and for pulmonary hypertension.
    • PGF2α:
      • Induces labor and therapeutic abortion; used for glaucoma treatment.

    Inhibitors of Eicosanoids

    • Corticosteroids: Inhibit phospholipase A2, blocking synthesis of all eicosanoids.
    • Non-steroidal anti-inflammatory drugs (NSAIDs):
      • Classical NSAIDs (e.g., aspirin) inhibit all COX enzymes non-selectively.
      • Newer NSAIDs (e.g., celecoxib) selectively inhibit COX-2.

    Eicosanoids Overview

    • Eicosanoids are fatty acid derivatives derived from arachidonic acid (20 carbons).
    • Main types include prostaglandins (PGs), thromboxanes (TXs), and leukotrienes (LTs).

    Prostaglandins (PGs)

    • Derived from arachidonic acid by cyclooxygenase (COX) enzymes.
    • Three isoforms of COX:
      • COX-1: Physiological role; synthesizes protective PGs (e.g., PGE2, PGI2) critical for stomach protection against HCl, renal blood flow regulation, and platelet aggregation inhibition.
      • COX-2: Inducible and involved in synthesizing undesirable PGs (e.g., PGF2α, PGD2) that contribute to inflammation and bronchoconstriction.
      • COX-3: A variant found in the brain, involved in fever and pain sensation; selectively inhibited by analgesics like acetaminophen.

    Thromboxanes (TXs)

    • Products of cyclooxygenase, primarily synthesized in platelets.
    • Two forms:
      • TXA2: Active form and potent stimulator of platelet aggregation.
      • TXB2: Inactive form.

    Leukotrienes (LTs)

    • Derived from arachidonic acid by lipoxygenase enzymes.
    • Main types: LTB4, LTC4, LTD4, and LTE4.
    • SRS-A (Slow-reacting substance of anaphylaxis) is a mixture of LTC4, LTD4, and LTE4, released during inflammatory response.
    • LTB4 is a strong bronchoconstrictor and a potent chemotactic factor for leukocytes.

    Pharmacological Actions of Eicosanoids

    • Eicosanoids interact with G-protein coupled receptors (DP1-2, EP1-4, FP, etc.).
    • Effects of various eicosanoids:
      • PGE1, PGE2: Vasodilation (VD), increased renal blood flow (RBF), bronchial relaxation.
      • PGI2: VD and anti-aggregation effects on platelets.
      • PGF2α: Vasoconstriction (VC), uterine contraction (both during pregnancy and non-pregnancy).
      • TXA2: Promotes platelet aggregation and VC.
      • LTB4: Contributes to edema and severe bronchoconstriction.

    Therapeutic Uses of Prostaglandins

    • PGE1 (Alprostadil):
      • Urethral inserts for erectile dysfunction; causes VD in corpus cavernosum.
      • Maintains ductus arteriosus patency in congenital heart diseases.
      • Treatment of peptic ulcers with Mesoprostol to prevent ulceration during NSAID use.
    • PGE2:
      • Induces labor (Dinoprostone) and treats peripheral vascular disease.
    • PGI2 (Prostacycline):
      • Inhibits platelet aggregation, used during surgery, dialysis, and for pulmonary hypertension.
    • PGF2α:
      • Induces labor and therapeutic abortion; used for glaucoma treatment.

    Inhibitors of Eicosanoids

    • Corticosteroids: Inhibit phospholipase A2, blocking synthesis of all eicosanoids.
    • Non-steroidal anti-inflammatory drugs (NSAIDs):
      • Classical NSAIDs (e.g., aspirin) inhibit all COX enzymes non-selectively.
      • Newer NSAIDs (e.g., celecoxib) selectively inhibit COX-2.

    Eicosanoids Overview

    • Eicosanoids are fatty acid derivatives derived from arachidonic acid (20 carbons).
    • Main types include prostaglandins (PGs), thromboxanes (TXs), and leukotrienes (LTs).

    Prostaglandins (PGs)

    • Derived from arachidonic acid by cyclooxygenase (COX) enzymes.
    • Three isoforms of COX:
      • COX-1: Physiological role; synthesizes protective PGs (e.g., PGE2, PGI2) critical for stomach protection against HCl, renal blood flow regulation, and platelet aggregation inhibition.
      • COX-2: Inducible and involved in synthesizing undesirable PGs (e.g., PGF2α, PGD2) that contribute to inflammation and bronchoconstriction.
      • COX-3: A variant found in the brain, involved in fever and pain sensation; selectively inhibited by analgesics like acetaminophen.

    Thromboxanes (TXs)

    • Products of cyclooxygenase, primarily synthesized in platelets.
    • Two forms:
      • TXA2: Active form and potent stimulator of platelet aggregation.
      • TXB2: Inactive form.

    Leukotrienes (LTs)

    • Derived from arachidonic acid by lipoxygenase enzymes.
    • Main types: LTB4, LTC4, LTD4, and LTE4.
    • SRS-A (Slow-reacting substance of anaphylaxis) is a mixture of LTC4, LTD4, and LTE4, released during inflammatory response.
    • LTB4 is a strong bronchoconstrictor and a potent chemotactic factor for leukocytes.

    Pharmacological Actions of Eicosanoids

    • Eicosanoids interact with G-protein coupled receptors (DP1-2, EP1-4, FP, etc.).
    • Effects of various eicosanoids:
      • PGE1, PGE2: Vasodilation (VD), increased renal blood flow (RBF), bronchial relaxation.
      • PGI2: VD and anti-aggregation effects on platelets.
      • PGF2α: Vasoconstriction (VC), uterine contraction (both during pregnancy and non-pregnancy).
      • TXA2: Promotes platelet aggregation and VC.
      • LTB4: Contributes to edema and severe bronchoconstriction.

    Therapeutic Uses of Prostaglandins

    • PGE1 (Alprostadil):
      • Urethral inserts for erectile dysfunction; causes VD in corpus cavernosum.
      • Maintains ductus arteriosus patency in congenital heart diseases.
      • Treatment of peptic ulcers with Mesoprostol to prevent ulceration during NSAID use.
    • PGE2:
      • Induces labor (Dinoprostone) and treats peripheral vascular disease.
    • PGI2 (Prostacycline):
      • Inhibits platelet aggregation, used during surgery, dialysis, and for pulmonary hypertension.
    • PGF2α:
      • Induces labor and therapeutic abortion; used for glaucoma treatment.

    Inhibitors of Eicosanoids

    • Corticosteroids: Inhibit phospholipase A2, blocking synthesis of all eicosanoids.
    • Non-steroidal anti-inflammatory drugs (NSAIDs):
      • Classical NSAIDs (e.g., aspirin) inhibit all COX enzymes non-selectively.
      • Newer NSAIDs (e.g., celecoxib) selectively inhibit COX-2.

    Eicosanoids Overview

    • Eicosanoids are fatty acid derivatives derived from arachidonic acid (20 carbons).
    • Main types include prostaglandins (PGs), thromboxanes (TXs), and leukotrienes (LTs).

    Prostaglandins (PGs)

    • Derived from arachidonic acid by cyclooxygenase (COX) enzymes.
    • Three isoforms of COX:
      • COX-1: Physiological role; synthesizes protective PGs (e.g., PGE2, PGI2) critical for stomach protection against HCl, renal blood flow regulation, and platelet aggregation inhibition.
      • COX-2: Inducible and involved in synthesizing undesirable PGs (e.g., PGF2α, PGD2) that contribute to inflammation and bronchoconstriction.
      • COX-3: A variant found in the brain, involved in fever and pain sensation; selectively inhibited by analgesics like acetaminophen.

    Thromboxanes (TXs)

    • Products of cyclooxygenase, primarily synthesized in platelets.
    • Two forms:
      • TXA2: Active form and potent stimulator of platelet aggregation.
      • TXB2: Inactive form.

    Leukotrienes (LTs)

    • Derived from arachidonic acid by lipoxygenase enzymes.
    • Main types: LTB4, LTC4, LTD4, and LTE4.
    • SRS-A (Slow-reacting substance of anaphylaxis) is a mixture of LTC4, LTD4, and LTE4, released during inflammatory response.
    • LTB4 is a strong bronchoconstrictor and a potent chemotactic factor for leukocytes.

    Pharmacological Actions of Eicosanoids

    • Eicosanoids interact with G-protein coupled receptors (DP1-2, EP1-4, FP, etc.).
    • Effects of various eicosanoids:
      • PGE1, PGE2: Vasodilation (VD), increased renal blood flow (RBF), bronchial relaxation.
      • PGI2: VD and anti-aggregation effects on platelets.
      • PGF2α: Vasoconstriction (VC), uterine contraction (both during pregnancy and non-pregnancy).
      • TXA2: Promotes platelet aggregation and VC.
      • LTB4: Contributes to edema and severe bronchoconstriction.

    Therapeutic Uses of Prostaglandins

    • PGE1 (Alprostadil):
      • Urethral inserts for erectile dysfunction; causes VD in corpus cavernosum.
      • Maintains ductus arteriosus patency in congenital heart diseases.
      • Treatment of peptic ulcers with Mesoprostol to prevent ulceration during NSAID use.
    • PGE2:
      • Induces labor (Dinoprostone) and treats peripheral vascular disease.
    • PGI2 (Prostacycline):
      • Inhibits platelet aggregation, used during surgery, dialysis, and for pulmonary hypertension.
    • PGF2α:
      • Induces labor and therapeutic abortion; used for glaucoma treatment.

    Inhibitors of Eicosanoids

    • Corticosteroids: Inhibit phospholipase A2, blocking synthesis of all eicosanoids.
    • Non-steroidal anti-inflammatory drugs (NSAIDs):
      • Classical NSAIDs (e.g., aspirin) inhibit all COX enzymes non-selectively.
      • Newer NSAIDs (e.g., celecoxib) selectively inhibit COX-2.

    Eicosanoids Overview

    • Eicosanoids are fatty acid derivatives derived from arachidonic acid (20 carbons).
    • Main types include prostaglandins (PGs), thromboxanes (TXs), and leukotrienes (LTs).

    Prostaglandins (PGs)

    • Derived from arachidonic acid by cyclooxygenase (COX) enzymes.
    • Three isoforms of COX:
      • COX-1: Physiological role; synthesizes protective PGs (e.g., PGE2, PGI2) critical for stomach protection against HCl, renal blood flow regulation, and platelet aggregation inhibition.
      • COX-2: Inducible and involved in synthesizing undesirable PGs (e.g., PGF2α, PGD2) that contribute to inflammation and bronchoconstriction.
      • COX-3: A variant found in the brain, involved in fever and pain sensation; selectively inhibited by analgesics like acetaminophen.

    Thromboxanes (TXs)

    • Products of cyclooxygenase, primarily synthesized in platelets.
    • Two forms:
      • TXA2: Active form and potent stimulator of platelet aggregation.
      • TXB2: Inactive form.

    Leukotrienes (LTs)

    • Derived from arachidonic acid by lipoxygenase enzymes.
    • Main types: LTB4, LTC4, LTD4, and LTE4.
    • SRS-A (Slow-reacting substance of anaphylaxis) is a mixture of LTC4, LTD4, and LTE4, released during inflammatory response.
    • LTB4 is a strong bronchoconstrictor and a potent chemotactic factor for leukocytes.

    Pharmacological Actions of Eicosanoids

    • Eicosanoids interact with G-protein coupled receptors (DP1-2, EP1-4, FP, etc.).
    • Effects of various eicosanoids:
      • PGE1, PGE2: Vasodilation (VD), increased renal blood flow (RBF), bronchial relaxation.
      • PGI2: VD and anti-aggregation effects on platelets.
      • PGF2α: Vasoconstriction (VC), uterine contraction (both during pregnancy and non-pregnancy).
      • TXA2: Promotes platelet aggregation and VC.
      • LTB4: Contributes to edema and severe bronchoconstriction.

    Therapeutic Uses of Prostaglandins

    • PGE1 (Alprostadil):
      • Urethral inserts for erectile dysfunction; causes VD in corpus cavernosum.
      • Maintains ductus arteriosus patency in congenital heart diseases.
      • Treatment of peptic ulcers with Mesoprostol to prevent ulceration during NSAID use.
    • PGE2:
      • Induces labor (Dinoprostone) and treats peripheral vascular disease.
    • PGI2 (Prostacycline):
      • Inhibits platelet aggregation, used during surgery, dialysis, and for pulmonary hypertension.
    • PGF2α:
      • Induces labor and therapeutic abortion; used for glaucoma treatment.

    Inhibitors of Eicosanoids

    • Corticosteroids: Inhibit phospholipase A2, blocking synthesis of all eicosanoids.
    • Non-steroidal anti-inflammatory drugs (NSAIDs):
      • Classical NSAIDs (e.g., aspirin) inhibit all COX enzymes non-selectively.
      • Newer NSAIDs (e.g., celecoxib) selectively inhibit COX-2.

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    Description

    This quiz explores the group of fatty acid derivatives known as eicosanoids, which are derived from arachidonic acid. Participants will learn about various eicosanoids including prostaglandins and their functions in the body. Test your knowledge on this important topic in biochemistry and physiology.

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