title: Requirement of Pretone by Thromboxane A(2) for Hypoxic Pulmonary Vasoconstriction in Precision-cut Lung Slices of Rat.
abstract: Hypoxic pulmonary vasoconstriction (HPV) is physiologically important response for preventing mismatching between ventilation and perfusion in lungs. The HPV of isolated pulmonary arteries (HPV-PA) usually require a partial pretone by thromboxane agonist (U46619). Because the HPV of ventilated/perfused lungs (HPV-lung) can be triggered without pretone conditioning, we suspected that a putative tissue factor might be responsible for the pretone of HPV. Here we investigated whether HPV can be also observed in precision-cut lung slices (PCLS) from rats. The HPV in PCLS also required partial contraction by U46619. In addition, K(+) channel blockers (4AP and TEA) required U46619-pretone to induce significant contraction of PA in PCLS. In contrast, the airways in PCLS showed reversible contraction in response to the K(+) channel blockers without pretone conditioning. Also, the airways showed no hypoxic constriction but a relaxation under the partial pretone by U46619. The airways in PCLS showed reliable, concentration-dependent contraction by metacholine (EC(50), ~210 nM). In summary, the HPV in PCLS is more similar to isolated PA than V/P lungs. The metacholine-induced constriction of bronchioles suggested that the PLCS might be also useful for studying airway physiology in situ.
authors.affiliation: Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Korea.
authors.forename: Su Jung
authors.initials: SJ
authors.lastname: Park
authors.forename: Hae Young
authors.initials: HY
authors.lastname: Yoo
authors.forename: Hye Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: Jin Kyoung
authors.initials: JK
authors.lastname: Kim
authors.forename: Yin-Hua
authors.initials: YH
authors.lastname: Zhang
authors.forename: Sung Joon
authors.initials: SJ
authors.lastname: Kim