Autocoids Flashcards
Eicosanoids are derived from which precursor?
Arachidonic acid
Name three main eicosanoids.
Prostaglandins, Thromboxanes, Leukotrienes
What enzyme is responsible for liberating arachidonic acid from cell membrane phospholipids?
Phospholipase A (PLA)
What are the isoforms of Cyclooxygenase (COX)?
COX-1, COX-2, COX-3
Which pathway is responsible for the conversion of arachidonic acid to leukotrienes?
Lipoxygenase pathway
What drug is a leukotriene receptor antagonist used in asthma?
Zafirkulast
What are the products of the Cyclooxygenase pathway?
Prostaglandins and Thromboxanes
Which prostaglandins are vasodilators?
PGI2 (prostacyclin), PGE2
Which prostaglandins are vasoconstrictors?
TXA2 (Thromboxane A2), PGF2α
What role does PGI2 play in platelet function?
Inhibits platelet aggregation
Which drug selectively inhibits COX-2?
Celecoxib
Lipoxins are derived from which fatty acid?
Arachidonic acid (ω-6 fatty acid)
What is the main role of lipoxins in inflammation?
Resolution of inflammation
Which leukotrienes are potent bronchoconstrictors involved in asthma?
LTC4, LTD4, LTE4
Which enzyme converts arachidonic acid to leukotrienes?
Lipoxygenase (5-LOASE)
Histamine is synthesized from which amino acid?
Histidine
Which histamine receptor is involved in allergic responses and vasodilation?
H1 receptor
Which histamine receptor is responsible for gastric acid secretion?
H2 receptor
Which serotonin receptor is involved in emesis (vomiting)?
5-HT3 receptor
What is the role of serotonin in the gastrointestinal tract?
Increases peristaltic movements
Which enzyme converts prekallikrein to kallikrein in the kinin system?
Haegeman factor (Factor XII)
Which two receptors mediate the effects of kinins?
B1 and B2 receptors
Endothelin-1 is primarily secreted by which type of cells?
Vascular endothelium cells
Which drug is a non-selective endothelin receptor antagonist used in pulmonary hypertension?
Bosentan
Nitric Oxide (NO) is synthesized from which amino acid?
L-arginine
What are the three isoforms of Nitric Oxide Synthase (NOS)?
nNOS (neuronal), eNOS (endothelial), iNOS (inducible)
What is the main effect of NO on vascular smooth muscles?
Vasodilation
Which class of drugs acts as NO donors to induce vasodilation?
Organic nitrates (e.g., nitroprusside)
Neurotensin acts as a neuromodulator and has therapeutic potential in which diseases?
Parkinson’s disease and schizophrenia
What is the primary role of Urotensin II in the body?
Acts as a potent vasoconstrictor
