Podcast
Questions and Answers
What is the primary function of COX-1 in the synthesis of prostaglandins?
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?
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?
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?
Which compound acts as the potent endogenous stimulator of platelet aggregation?
Which prostaglandin is NOT produced by COX-1 activity?
Which prostaglandin is NOT produced by COX-1 activity?
What role does acetaminophen play in relation to COX-3?
What role does acetaminophen play in relation to COX-3?
Which of the following is a feature of thromboxanes (TXs)?
Which of the following is a feature of thromboxanes (TXs)?
What is a characteristic of COX-2 activity?
What is a characteristic of COX-2 activity?
What is the primary role of PGE1 in neonates and infants?
What is the primary role of PGE1 in neonates and infants?
Which of the following conditions can PGE2 be used to treat?
Which of the following conditions can PGE2 be used to treat?
What is the mechanism of action of Mesoprostol in patients taking NSAIDs?
What is the mechanism of action of Mesoprostol in patients taking NSAIDs?
Which prostaglandin is primarily used to treat open-angle glaucoma?
Which prostaglandin is primarily used to treat open-angle glaucoma?
What is a key function of PGI2 (Prostacyclin)?
What is a key function of PGI2 (Prostacyclin)?
What distinguishes newer NSAIDs like celecoxib from classical NSAIDs?
What distinguishes newer NSAIDs like celecoxib from classical NSAIDs?
Which class of drugs inhibits the synthesis of all eicosanoids by blocking phospholipase A2?
Which class of drugs inhibits the synthesis of all eicosanoids by blocking phospholipase A2?
What effect does PGF2α have when used with mifepristone?
What effect does PGF2α have when used with mifepristone?
What are the main types of leukotrienes?
What are the main types of leukotrienes?
Which leukotriene is known for its powerful bronchoconstrictor and chemotactic properties?
Which leukotriene is known for its powerful bronchoconstrictor and chemotactic properties?
Which of the following eicosanoids promotes vasodilation?
Which of the following eicosanoids promotes vasodilation?
What is the action of PGE1 in the treatment of erectile dysfunction?
What is the action of PGE1 in the treatment of erectile dysfunction?
Which eicosanoid primarily causes contraction of the non-pregnant uterus?
Which eicosanoid primarily causes contraction of the non-pregnant uterus?
What is the effect of LTB4 on platelet aggregation?
What is the effect of LTB4 on platelet aggregation?
What role does PGE1 play for infants with congenital cyanotic heart diseases?
What role does PGE1 play for infants with congenital cyanotic heart diseases?
Which eicosanoid is associated with chemotaxis?
Which eicosanoid is associated with chemotaxis?
COX-1 is primarily involved in the synthesis of undesirable prostaglandins.
COX-1 is primarily involved in the synthesis of undesirable prostaglandins.
Thromboxane A2 is the inactive form of thromboxanes.
Thromboxane A2 is the inactive form of thromboxanes.
The central isoform of cyclooxygenase is known as COX-3 and is selectively inhibited by analgesic drugs.
The central isoform of cyclooxygenase is known as COX-3 and is selectively inhibited by analgesic drugs.
Prostaglandins are derived from fatty acids that contain more than 20 carbons.
Prostaglandins are derived from fatty acids that contain more than 20 carbons.
The action of cyclooxygenase enzymes results in the synthesis of both thromboxanes and leukotrienes.
The action of cyclooxygenase enzymes results in the synthesis of both thromboxanes and leukotrienes.
Prostaglandin E2 (PGE2) plays a role in protecting the stomach from hydrochloric acid.
Prostaglandin E2 (PGE2) plays a role in protecting the stomach from hydrochloric acid.
COX-2 is constitutively expressed in platelets.
COX-2 is constitutively expressed in platelets.
Both COX-1 and COX-2 isoforms are involved in the synthesis of thromboxanes.
Both COX-1 and COX-2 isoforms are involved in the synthesis of thromboxanes.
Mesoprostol is approved to treat excessive gastrointestinal bleeding in patients taking NSAIDs.
Mesoprostol is approved to treat excessive gastrointestinal bleeding in patients taking NSAIDs.
PGI2, also known as Prostacyclin, can inhibit platelet aggregation.
PGI2, also known as Prostacyclin, can inhibit platelet aggregation.
PGE2 is primarily indicated for the treatment of open-angle glaucoma by reducing intraocular pressure.
PGE2 is primarily indicated for the treatment of open-angle glaucoma by reducing intraocular pressure.
Corticosteroids inhibit the synthesis of certain eicosanoids by blocking cyclooxygenase enzymes.
Corticosteroids inhibit the synthesis of certain eicosanoids by blocking cyclooxygenase enzymes.
The action of PGF2α includes the induction of labor and therapeutic abortion.
The action of PGF2α includes the induction of labor and therapeutic abortion.
Celecoxib selectively inhibits COX-1 while sparing COX-2 in its action.
Celecoxib selectively inhibits COX-1 while sparing COX-2 in its action.
Thromboxanes and leukotrienes currently have significant clinical applications.
Thromboxanes and leukotrienes currently have significant clinical applications.
Induction of labor can be achieved using both Dinoprostone and Enzaprost.
Induction of labor can be achieved using both Dinoprostone and Enzaprost.
Leukotrienes are derived from arachidonic acid by the action of cyclooxygenase enzymes.
Leukotrienes are derived from arachidonic acid by the action of cyclooxygenase enzymes.
LTB4 is a powerful bronchoconstrictor and chemotactic for leukocytes.
LTB4 is a powerful bronchoconstrictor and chemotactic for leukocytes.
PGE1 is used exclusively to maintain patency of the ductus arteriosus in infants.
PGE1 is used exclusively to maintain patency of the ductus arteriosus in infants.
The therapeutic use of PGF2α includes promoting vasodilation in smooth muscle.
The therapeutic use of PGF2α includes promoting vasodilation in smooth muscle.
The slow-reacting substance of anaphylaxis (SRS-A) is a mixture of LTC4, LTD4, and LTE4.
The slow-reacting substance of anaphylaxis (SRS-A) is a mixture of LTC4, LTD4, and LTE4.
Prostaglandins act on cell surface G-protein coupled receptors classified as FP, EP, DP1, and DP2.
Prostaglandins act on cell surface G-protein coupled receptors classified as FP, EP, DP1, and DP2.
TXA2 induces platelet aggregation while PGE2 decreases it.
TXA2 induces platelet aggregation while PGE2 decreases it.
LTB4 is known to promote edema formation.
LTB4 is known to promote edema formation.
What enzyme is involved in the synthesis of leukotrienes from arachidonic acid?
What enzyme is involved in the synthesis of leukotrienes from arachidonic acid?
Which leukotrienes constitute the slow-reacting substance of anaphylaxis (SRS-A)?
Which leukotrienes constitute the slow-reacting substance of anaphylaxis (SRS-A)?
What are the effects of LTB4 on leukocytes?
What are the effects of LTB4 on leukocytes?
Describe the vasodilatory effects of PGE2 and PGI2.
Describe the vasodilatory effects of PGE2 and PGI2.
How does PGE1 function in the treatment of erectile dysfunction?
How does PGE1 function in the treatment of erectile dysfunction?
What is the impact of TXA2 on platelet aggregation?
What is the impact of TXA2 on platelet aggregation?
Which eicosanoid is primarily responsible for the contraction of the pregnant uterus?
Which eicosanoid is primarily responsible for the contraction of the pregnant uterus?
What is the primary therapeutic use of PGE1 in neonates?
What is the primary therapeutic use of PGE1 in neonates?
Explain the role of PGE1 in the management of ductus arteriosus in neonates.
Explain the role of PGE1 in the management of ductus arteriosus in neonates.
How do corticosteroids affect eicosanoid synthesis?
How do corticosteroids affect eicosanoid synthesis?
Compare the mechanisms of action between classical NSAIDs and COX-2 selective inhibitors like celecoxib.
Compare the mechanisms of action between classical NSAIDs and COX-2 selective inhibitors like celecoxib.
Discuss the clinical applications of PGI2 (Prostacyclin).
Discuss the clinical applications of PGI2 (Prostacyclin).
What is the significance of combining PGF2α with mifepristone in therapeutic abortion?
What is the significance of combining PGF2α with mifepristone in therapeutic abortion?
Analyze the use of Mesoprostol in patients with NSAID-induced gastric ulcers.
Analyze the use of Mesoprostol in patients with NSAID-induced gastric ulcers.
Describe the function of PGF2α in obstetrics.
Describe the function of PGF2α in obstetrics.
What is the role of PGE2 in the treatment of open-angle glaucoma?
What is the role of PGE2 in the treatment of open-angle glaucoma?
What are the main functions of COX-1 derived prostaglandins in physiological processes?
What are the main functions of COX-1 derived prostaglandins in physiological processes?
Describe the role of COX-2 in the context of inflammatory responses.
Describe the role of COX-2 in the context of inflammatory responses.
What distinguishes thromboxane A2 (TXA2) from its inactive form TXB2?
What distinguishes thromboxane A2 (TXA2) from its inactive form TXB2?
How does the presence of COX-3 in the central nervous system affect pain sensation?
How does the presence of COX-3 in the central nervous system affect pain sensation?
Explain the significance of prostaglandins in gastric protection and renal function.
Explain the significance of prostaglandins in gastric protection and renal function.
What is the impact of acetaminophen on COX-3 activity?
What is the impact of acetaminophen on COX-3 activity?
In what way do the isoforms of cyclooxygenase (COX) differ in their physiological and pathological roles?
In what way do the isoforms of cyclooxygenase (COX) differ in their physiological and pathological roles?
What relationship do eicosanoids have with arachidonic acid metabolism?
What relationship do eicosanoids have with arachidonic acid metabolism?
Prostaglandins (PGs) are derived from arachidonic acid by the action of ______ enzyme.
Prostaglandins (PGs) are derived from arachidonic acid by the action of ______ enzyme.
COX-1 is involved in the synthesis of protective prostaglandins responsible for the ______ of the stomach from hydrochloric acid.
COX-1 is involved in the synthesis of protective prostaglandins responsible for the ______ of the stomach from hydrochloric acid.
Thromboxane A2 (TXA2) is the most potent endogenous stimulator of ______ aggregation.
Thromboxane A2 (TXA2) is the most potent endogenous stimulator of ______ aggregation.
COX-2 is primarily involved in the synthesis of undesirable prostaglandins implicated in ______ reactions.
COX-2 is primarily involved in the synthesis of undesirable prostaglandins implicated in ______ reactions.
COX-3 is a variant of COX-2 that is primarily found in the ______.
COX-3 is a variant of COX-2 that is primarily found in the ______.
Dipyrones and acetaminophen selectively inhibit ______ to reduce fever and pain.
Dipyrones and acetaminophen selectively inhibit ______ to reduce fever and pain.
Thromboxanes are synthesized in high concentration in ______.
Thromboxanes are synthesized in high concentration in ______.
The active form of thromboxanes is known as ______ A2.
The active form of thromboxanes is known as ______ A2.
Leukotrienes are derived from arachidonic acid by the action of ________ enzyme.
Leukotrienes are derived from arachidonic acid by the action of ________ enzyme.
A mixture of LTC4, LTD4, and LTE4 is termed the slow-reacting substance of ________.
A mixture of LTC4, LTD4, and LTE4 is termed the slow-reacting substance of ________.
LTB4 is a powerful ________ and chemotactic for leukocytes.
LTB4 is a powerful ________ and chemotactic for leukocytes.
PGE1 (Alprostadil) is used as a treatment for erectile dysfunction by producing ________ of the vascular smooth muscle.
PGE1 (Alprostadil) is used as a treatment for erectile dysfunction by producing ________ of the vascular smooth muscle.
Different eicosanoids act on cell surface ________-protein coupled receptors.
Different eicosanoids act on cell surface ________-protein coupled receptors.
In pregnant women, the action of prostaglandins includes ________ of the uterus.
In pregnant women, the action of prostaglandins includes ________ of the uterus.
The pharmacological actions of eicosanoids include promoting ________ in blood vessels.
The pharmacological actions of eicosanoids include promoting ________ in blood vessels.
The therapeutic uses of PGE1 include maintaining patency of the ________ arteriosus in infants.
The therapeutic uses of PGE1 include maintaining patency of the ________ arteriosus in infants.
The ductus arteriosus is necessary for additional oxygenation until surgical correction is undertaken in neonates and ______.
The ductus arteriosus is necessary for additional oxygenation until surgical correction is undertaken in neonates and ______.
Mesoprostol is approved for use in patients taking high doses of NSAIDs to prevent gastric ______.
Mesoprostol is approved for use in patients taking high doses of NSAIDs to prevent gastric ______.
Dinoprostone is used for the induction of labor near full term and is a form of ______.
Dinoprostone is used for the induction of labor near full term and is a form of ______.
Prostacyclin, or ______, is used to inhibit platelet aggregation during certain medical procedures.
Prostacyclin, or ______, is used to inhibit platelet aggregation during certain medical procedures.
Therapeutic abortion can involve the use of PGF2α as vaginal ______.
Therapeutic abortion can involve the use of PGF2α as vaginal ______.
Corticosteroids inhibit the synthesis of all the eicosanoids family by blocking the enzyme ______ A2.
Corticosteroids inhibit the synthesis of all the eicosanoids family by blocking the enzyme ______ A2.
Newer NSAIDs, like celecoxib, selectively inhibit ______-2.
Newer NSAIDs, like celecoxib, selectively inhibit ______-2.
Induction of labor can also be achieved using ______ in addition to Dinoprostone.
Induction of labor can also be achieved using ______ in addition to Dinoprostone.
Match the following eicosanoids with their primary function:
Match the following eicosanoids with their primary function:
Match the cyclooxygenase isoforms with their characteristics:
Match the cyclooxygenase isoforms with their characteristics:
Match the following prostaglandins with their associated effects:
Match the following prostaglandins with their associated effects:
Match the action of acetaminophen with the associated cyclooxygenase isoform:
Match the action of acetaminophen with the associated cyclooxygenase isoform:
Match the effects of thromboxanes with their impact:
Match the effects of thromboxanes with their impact:
Match the types of eicosanoids with their categories:
Match the types of eicosanoids with their categories:
Match the conditions with the prostaglandins that may treat them:
Match the conditions with the prostaglandins that may treat them:
Match the features of eicosanoids with their definitions:
Match the features of eicosanoids with their definitions:
Match the eicosanoids with their primary effects:
Match the eicosanoids with their primary effects:
Match the types of leukotrienes with their corresponding codes:
Match the types of leukotrienes with their corresponding codes:
Match the therapeutic uses of prostaglandins with their corresponding drug:
Match the therapeutic uses of prostaglandins with their corresponding drug:
Match the effects of eicosanoids on blood vessels:
Match the effects of eicosanoids on blood vessels:
Match the action of leukotrienes with their specific effects:
Match the action of leukotrienes with their specific effects:
Match the prostaglandin with its primary therapeutic use:
Match the prostaglandin with its primary therapeutic use:
Match the eicosanoids with their vasodilatory or vasoconstrictory effects:
Match the eicosanoids with their vasodilatory or vasoconstrictory effects:
Match the drug to its mechanism of action:
Match the drug to its mechanism of action:
Match the eicosanoids with their regulatory roles:
Match the eicosanoids with their regulatory roles:
Match the condition with the relevant prostaglandin:
Match the condition with the relevant prostaglandin:
Match the receptors with the eicosanoid they primarily bind to:
Match the receptors with the eicosanoid they primarily bind to:
Match the class of drug with its site of action:
Match the class of drug with its site of action:
Match the eicosanoid with its physiological effect:
Match the eicosanoid with its physiological effect:
Match the indication with the specific prostaglandin:
Match the indication with the specific prostaglandin:
Match the prostaglandin with its associated complication or condition:
Match the prostaglandin with its associated complication or condition:
Match the clinical use with the drug mechanism:
Match the clinical use with the drug mechanism:
Flashcards are hidden until you start studying
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.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
