BACKGROUND: The roles of arachidonic acid (AA) metabolites in hypoxia-induced pulmonary vasoconstriction (HPV), a critical physiological mechanism that prevents ventilation/perfusion mismatch, are still incompletely understood. METHODS: Pulmonary arterial pressure was measured in ventilated/perfused rat lungs. Isometric tones of rat intralobar pulmonary arteries were also measured, using a myograph. RESULTS: Hypoxia (Po₂, 3%)-induced pulmonary arterial pressure increases (ΔPAP(hypox)) were stable with blood-mixed perfusate, but decayed spontaneously. ΔPAP(hypox) was inhibited by 29%, 16%, and 28% by the thromboxane A₂ (TXA₂) antagonist SQ-29548, the 5-lipoxygenase inhibitor, MK886, and the leukotriene D₄ antagonist, LY-171883, respectively. The prostacyclin synthase inhibitor tranylcypromine augmented ΔPAP(hypox) by 5%, whereas inhibition of cytochrome P450 did not affect ΔPAP(hypox). Consistently, the TXA₂ analogue U46619 increased ΔPAP(hypox) whereas prostacyclin abolished ΔPAP(hypox). However, leukotriene D₄ had no direct effect on ΔPAP(hypox). In the isolated pulmonary arteries, pretreatment with U46619 was essential to demonstrate hypoxia-induced contraction. CONCLUSIONS: The above results suggest that TXA₂ and cysteinyl leukotrienes, other than leukotriene D₄, are endogenous factors that facilitate HPV in rats. The indispensable role of TXA₂-induced pretone in the HPV of isolated pulmonary arteries indicates that the signal from thromboxane receptors might be a critical component of oxygen sensation mechanisms.
BACKGROUND: The roles of arachidonic acid (AA) metabolites in hypoxia-induced pulmonary vasoconstriction (HPV), a critical physiological mechanism that prevents ventilation/perfusion mismatch, are still incompletely understood. METHODS: Pulmonary arterial pressure was measured in ventilated/perfused rat lungs. Isometric tones of rat intralobar pulmonary arteries were also measured, using a myograph. RESULTS:Hypoxia (Po₂, 3%)-induced pulmonary arterial pressure increases (ΔPAP(hypox)) were stable with blood-mixed perfusate, but decayed spontaneously. ΔPAP(hypox) was inhibited by 29%, 16%, and 28% by the thromboxane A₂ (TXA₂) antagonist SQ-29548, the 5-lipoxygenase inhibitor, MK886, and the leukotriene D₄ antagonist, LY-171883, respectively. The prostacyclin synthase inhibitor tranylcypromine augmented ΔPAP(hypox) by 5%, whereas inhibition of cytochrome P450 did not affect ΔPAP(hypox). Consistently, the TXA₂ analogue U46619 increased ΔPAP(hypox) whereas prostacyclin abolished ΔPAP(hypox). However, leukotriene D₄ had no direct effect on ΔPAP(hypox). In the isolated pulmonary arteries, pretreatment with U46619 was essential to demonstrate hypoxia-induced contraction. CONCLUSIONS: The above results suggest that TXA₂ and cysteinyl leukotrienes, other than leukotriene D₄, are endogenous factors that facilitate HPV in rats. The indispensable role of TXA₂-induced pretone in the HPV of isolated pulmonary arteries indicates that the signal from thromboxane receptors might be a critical component of oxygen sensation mechanisms.
Authors: Hae Jin Kim; Hae Young Yoo; Ji Hyun Jang; Hai Yue Lin; Eun Yeong Seo; Yin Hua Zhang; Sung Joon Kim Journal: Pflugers Arch Date: 2016-01-04 Impact factor: 3.657
Authors: Xizhong Cui; Jeffrey Wang; Yan Li; Zoe G Couse; Thomas F Risoleo; Mahtab Moayeri; Stephen H Leppla; Daniela Malide; Zu-Xi Yu; Peter Q Eichacker Journal: Am J Physiol Heart Circ Physiol Date: 2020-10-16 Impact factor: 4.733
Authors: Hae Young Yoo; Amy Zeifman; Eun A Ko; Kimberly A Smith; Jiwang Chen; Roberto F Machado; You-Yang Zhao; Richard D Minshall; Jason X-J Yuan Journal: Pulm Circ Date: 2013-04 Impact factor: 3.017
Authors: Su Jung Park; Hae Young Yoo; Hye Jin Kim; Jin Kyoung Kim; Yin-Hua Zhang; Sung Joon Kim Journal: Korean J Physiol Pharmacol Date: 2012-02-28 Impact factor: 2.016