title: Essential role of L-arginine uptake and protein tyrosine kinase activity for NO-dependent vasorelaxation induced by stretch, isometric tension and cyclic AMP in rat pulmonary arteries.
abstract: 1. The NO-dependent component of cyclic AMP-induced vasorelaxation in rat pulmonary arteries is critically dependent on extracellular L-arginine but independent of endothelial cell intracellular [Ca(2+)]. We examined whether L-arginine uptake was also essential for NO production induced by passive stretch or isometric tension, processes also reported to be Ca(2+)-independent. 2. The passive length-tension curve was depressed by physiological concentrations of L-arginine (400 microM; P<0.05). Inhibition of the y(+) transporter with 10 mM L-lysine, NO synthase with L-NAME (100 microM), or protein tyrosine kinase with erbstatin A (30 microM) caused identical upward shifts (P<0.001), alone or in combination. Tyrphostin 23 was similar to erbstatin A, whilst the inactive analogue tyrphostin A1 and genistein were without effect. 3. L-arginine (400 microM) shifted the PGF(2 alpha) concentration-response curve under isometric conditions to the right (P<0.05), whereas L-NAME or L-lysine caused a leftward shift (P<0.001). Tyrphostin 23 (30 microM) more than reversed the L-arginine-induced suppression of PGF(2 alpha)-induced tension; subsequent addition of L-NAME had no effect. The L-lysine-sensitive component of CPT cyclic AMP-induced vasorelaxation was abolished by erbstatin A. 4. ACh-induced vasorelaxation was approximately 80% inhibited by L-NAME, but was not affected by L-lysine or 400 microM L-arginine. Erbstatin A reduced the vasorelaxation by only approximately 25%. 5. We conclude that activation of NO production by stretch, isometric tension, or cyclic AMP in rat pulmonary arteries is critically dependent on the presence and uptake of physiological concentrations of extracellular L-arginine, and protein tyrosine kinase activity. This directly contrasts with ACh-induced vasorelaxation, which was independent of extracellular L-arginine, and relatively unaffected by tyrosine kinase inhibition.
authors.affiliation: Department of Respiratory Medicine and Allergy, Guy's, King's and St Thomas' School of Medicine, King's College London, Guy's Campus, London SE1 9RT.
authors.forename: D
authors.initials: D
authors.lastname: Hucks
authors.forename: N M
authors.initials: NM
authors.lastname: Khan
authors.forename: J P
authors.initials: JP
authors.lastname: Ward
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001120:Arginine / Q000493:pharmacokinetics*; D000242:Cyclic AMP / Q000031:analogs & derivatives* / Q000494:pharmacology*; D015237:Dinoprost / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006873:Hydroquinones / Q000494:pharmacology; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000502:physiology*; D008239:Lysine / Q000494:pharmacology; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000502:physiology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011651:Pulmonary Artery / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D013314:Stress, Mechanical; D013873:Thionucleotides / Q000494:pharmacology; D020032:Tyrphostins / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D006873:Hydroquinones; D013873:Thionucleotides; D020032:Tyrphostins; D014665:Vasodilator Agents; D009569:Nitric Oxide; C015929:8-((4-chlorophenyl)thio)cyclic-3',5'-AMP; D001120:Arginine; D015237:Dinoprost; D000242:Cyclic AMP; D011505:Protein-Tyrosine Kinases; D008239:Lysine; D000109:Acetylcholine; D019331:NG-Nitroarginine Methyl Ester; C048212:erbstatin