Prostanoids + COX-1/COX-2

Gs

GPCR that activates adenylyl cyclase, increasing cAMP, which activates protein kinase A (PKA); causes smooth muscle relaxation and platelet inhibition

Gi

GPCR that inhibits adenylyl cyclase and decreases cAMP; this upregulates platelet aggregation

Gq

GPCR that activates phospholipase C (PLC), generating IP₃ and DAG; this increases intracellular Ca²⁺, favoring smooth muscle contraction

PGD₂

Produced by mast cells during allergic inflammation responses; recruits/activates Th2 cells, eosinophils, and basophils; causes vasodilation

DP1

Gs receptor that causes relaxation/vasodilatory effects in some tissues

DP2

Gi receptor that recruits and activates inflammatory cells

PGE₁/PGE₂

Versatile prostanoid that participates in vascular regulation, gastric mucosal protection, uterine/cervical function, inflammation, pain, and fever

EP1

Gq receptor that increases calcium concentration and promotes muscle contraction (bronchoconstriction)

EP2/EP4

Gs receptor that favors muscle relaxation (vasodilation, bronchodilation, fever, inflammation)

EP3

Gi receptor that stimulates uterine contraction, gastric mucus secretion, and inhibits gastric acid secretion

PGF₂a

Prostanoid that promotes uterine myometrial contraction, lowers intraocular pressure (via uveoscleral outflow), an can increase contractile tone in some tissues; less preferred for inducing labor

FP

Gq receptor that promotes uterine myometrial contraction, lowers intraocular pressure, and can increase contractile tone in some tissues

PGI₂

Prostanoid that causes vasodilation, suppresses platelet activation, inhibits platelet aggregation, and regulates mucosal blood flow

IP

Gs receptor that causes vasodilation and relaxation in smooth muscle and suppresses platelet activation and aggregation

TXA₂

Prostanoid that causes vasoconstriction and platelet activation + aggregation

TP

Gq receptor that causes vasoconstriction and increased platelet aggregation

PGE₁

Prostanoid that causes vasodilation, facilitates erections, and maintains the patent ductus arteriosus

PGE₂

Prostanoid that stimulates uterine contraction and promotes GI epithelial mucus and bicarbonate secretion; preferred for inducing labor

PGH₂

Precursor of prostaglandins, prostacyclin, and thromboxane; produced from arachidonic acid via COX-1 & COX-2

Aspirin

Irreversibly acetylates serine 530 in the COX active site, inhibiting platelet activation and aggregation

Celecoxib

Only COX-2-selective NSAID; inhibits PGI₂ synthesis, which increases risk of thrombosis

COX-1

Enzyme that is strongly associated with homeostatic functions such as gastric mucosal protection and platelet production; has isoleucine in 523 spot

COX-2

Enzyme that is strongly associated with inflammation, pain, fever, and some renal and vascular functions; has valine in 523 spot

Profens

Non-selective COX inhibitors that cause rapid and reversible inhibition; sold as racemic mixture, but only S enantiomer is active

Naproxen

Non-selective COX inhibitor that inhibits slowly and reversibly; sold only as the active S-enantiomer; long half-life

Acetaminophen

Antipyretic and analgesic that inhibits prostaglandin production when peroxide and arachidonic acid levels are low; weak anti-inflammatory activity