]> 2026-07-31T16:29:08+00:00 WBR0736 0 en A LTB4 plays a major role in neutrophil chemotaxis. B LTC4 and LTD4 are important to increase bronchial tone. They play a role in inflammatory bronchoconstrictive lung diseases, such as asthma. C The classical role of prostacyclin (PGI2) is the prevention of platelet aggregation. It also decreases vascular, bronchial, and uterine tonicity. D Prostaglandins share some characteristics with prostacyclin; they decrease vascular and bronchial tone. However, they have an opposing role in uterine tonicity, where they increase uterine tone. As such, prostaglandin analogs may be used in conjunction with other drugs to induce labor in pregnancy. E Thromboxane (TXA2) has an opposing role to prostacyclin in platelets. It increases platelet aggregation. Also, it increases both vascular and bronchial tonicity. Neutrophils are key components of the innate immune response. They are the first cells to respond to bacterial infections, areas of inflammation, and wound sites. To achieve adequate chemotaxis, which is defined as migration to sites of inflammation, intracellular signaling pathways, which are spacially and temporally regulated, help the neutrophil identify gradients of chemoattractants, such as LBT4, before it undergoes polarization and physical migration. Endogenous and exogenous chemoattractants allow the neutrophil to alter its morphological appearance to achieve polarization that aids in orientation during migration. Chemotaxis is thus an important feature of neutrophil activity. The pathway shown in the image is the arachidonic acid pathway that involves 2 main enzymes: Lipoxygenase which forms hydroperoxides to yield leukotrienes, and cyclooxygenase (COX), which forms endoperoxides. The 2 enzymes have significant roles in unrelated domains. In the pathway, LTB4 is an important neutrophil chemotactic agent.<br/> '''Educational Objective:''' LTB4 is an important neutrophil chemotactic agent.<br/> '''References:''' Nuzzi PA, Lokuta MA, Huttenlocher A. Analysis of neutrophil chemotaxis. Methods Mol Biol. 2007;370:23-36.<br> First Aid 2014 page 224 and 439 Immunology A Hematology 2020-10-28T01:31:40Z 2459150.5636574 WBR0736