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Inhibition of nitric oxide synthesis potentiates hypoxic vasoconstriction in isolated rat lungs
Author(s) -
Robertson BE,
Warren JB,
Nye PC
Publication year - 1990
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1113/expphysiol.1990.sp003399
Subject(s) - nitric oxide , hypoxic pulmonary vasoconstriction , vasoconstriction , hypoxia (environmental) , chemistry , pharmacology , medicine , biology , oxygen , organic chemistry
We have investigated the influence of endogenous nitric oxide (NO) on the vascular resistance of isolated rat lungs by inhibiting its synthesis with the false substrate N‐monomethyl‐L‐arginine (L‐NMMA). When perfused with blood at constant flow the addition of L‐NMMA (10(‐3) M) did not affect pulmonary arterial pressure in hyperoxia but did increase the response to hypoxia (PO2 25‐35 mmHg) by 2.5 +/‐ 0.2 fold (mean +/‐ S.E.M.). The effect of L‐NMMA was reversed by 3 x 10(‐3) M‐L‐arginine, the true substrate for NO synthesis. Thus NO is an important pulmonary vasodilator but hypoxic vasoconstriction does not result from a reduction of its background release.