Prostaglandins and Related Autacoids Lecture Flashcards

A set of 20 vocabulary-style flashcards covering the synthesis, subfamilies, receptors, and clinical uses of eicosanoids based on lecture materials.

Eicosanoids

Signaling molecules made by the enzymatic or non-enzymatic oxidation of arachidonic acid or other polyunsaturated fatty acids.

Phospholipase $A_2$

The enzyme responsible for cleaving polyunsaturated 20-carbon fatty acids from membrane phospholipids.

Arachidonic acid

$5,8,11,14\text{-eicosatetraenoic acid}$, the parent fatty acid for the synthesis of prostaglandins, thromboxanes, and leukotrienes.

COX-1

A cyclooxygenase isoform that is constitutively expressed regardless of physiological demands.

COX-2

An inducible cyclooxygenase isoform expressed in response to inflammatory mediators such as cytokines and liposaccharides.

Autacoids

Substances that primarily act as local hormones and are synthesized and secreted in response to diverse stimuli rather than being stored.

Prostacyclin ($PGI_2$)

A prostanoid that binds to IP receptors to cause vasodilatation and the inhibition of platelet aggregation.

Thromboxane $A_2$ ($TXA_2$)

A prostanoid that binds to TP receptors, leading to platelet aggregation and bronchoconstriction.

Prostaglandin $E_2$ ($PGE_2$)

A prostanoid that serves as a mediator of fever and inflammatory responses, often found in high concentrations in CSF during infections.

$EP_3$ Receptor

A prostaglandin receptor type for $PGE_2$ that, when activated, decreases gastric acid and gastric mucus secretion.

Prostaglandin $F_{2\alpha}$ ($PGF_{2\alpha}$)

A prostanoid acting on FP receptors to cause contraction of the uterus, bronchoconstriction, and aqueous humor drainage.

Misoprostol ($PGE_1$)

A prostaglandin analogue used for the termination of pregnancy (abortifacient) and to prevent peptic ulcers in patients taking NSAIDs.

Dinoprostone ($PGE_2$)

A prostaglandin used clinically for the induction of labour.

Alprostadil ($PGE_1$)

A prostaglandin used to maintain the patency of the ductus arteriosus in congenital heart malformations or to treat impotence.

Latanoprost

A $PGF_{2\alpha}$ analogue used for open-angle glaucoma that can cause permanent eye color change.

5-Lipoxygenase

The enzyme pathway by which leukotrienes are derived from arachidonic acid ($\text{eicosatetraenoic acid}$).

5-HPETE

$5\text{-hydroperoxyeicosatetraenoic acids}$, an intermediate molecule in the synthesis of leukotrienes.

Montelukast

A competitive inhibitor of $LTC_4$, $LTD_4$, and $LTE_4$ at the $Cys\text{-}LT_1$ receptor used for asthma prophylaxis.

Zileuton

A competitive inhibitor of 5-lipoxygenase used in the treatment of asthma.

Zafirlukast

A drug that acts by blocking leukotriene receptors to treat asthma.