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Regulation of baseline vascular resistance in the canine diaphragm by nitric oxide
Author(s) -
Ward Michael E.,
Hussain Sabah N.A.
Publication year - 1994
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1994.tb13030.x
Subject(s) - nitric oxide , arginine , sodium nitroprusside , acetylcholine , vascular resistance , medicine , vasodilation , endothelium , endocrinology , citrulline , omega n methylarginine , nitric oxide synthase , pharmacology , biology , biochemistry , amino acid , blood pressure
1 The role played by nitric oxide (NO) in the regulation of blood flow to the canine isolated hemidiaphragm was evaluated by determining (a) the effects of the l ‐arginine analogues N G ‐nitro‐ l ‐arginine methyl ester ( l ‐NAME), N G ‐nitro‐ l ‐arginine ( l ‐NOARG), and argininosuccinic acid (ArgSA) on baseline vascular resistance and of the latter two agents on endothelium‐dependent (acetylcholine, ACh) and endothelium independent (sodium nitroprusside, SNP) vasodilatation; (b) the effects of l ‐ and d ‐arginine on baseline vascular resistance; and (c) the effects of l ‐glutamine, an inhibitor of intracellular recycling of l ‐citrulline to l ‐arginine, on baseline resistance and on the response to ACh and SNP. 2 l‐ NAME, l ‐NOARG and ArgSA (6 × 10 −4 m final concentration) increased baseline diaphragmatic vascular resistance to a similar extent (28.6 ± 4.2%, 26.7 ± 4.3% and 32.8 ± 4.6% respectively). l ‐NOARG and ArgSA reversed the vasodilator effect of ACh but not of SNP. 3 l ‐ and d ‐arginine had no effect on vascular resistance. 4 l ‐Glutamine (10 −3 m ) increased baseline vascular resistance by 10 ± 1.9% ( P < 0.05) but did not alter responses to either ACh or SNP. 5 Basal NO release plays a role in the regulation of baseline diaphragmatic vascular resistance. l ‐Arginine analogues tested potently and specifically inhibited this process. Moreover, extracellular l ‐arginine appears to have no effect on baseline diaphragmatic vascular resistance.