Bronchoconstriction and endogenous nitric oxide in isolated lungs of spontaneously hypertensive rats.
Bronchoconstrictor responses were measured in lungs isolated from spontaneously hypertensive (SHR) and normotensive rats, perfused via the airways. Lungs from SHRs were more responsive than lungs from normotensive rats to methacholine, 5-hydroxytryptamine (5-HT), arachidonic acid or prostaglandin H(2). The responses of SHR airways to methacholine or 5-HT were unaffected by pretreatment in vivo with an inhibitor of nitric oxide (NO) synthase, N(omega)-nitro-L-arginine methyl ester hydrochloride (L-NAME, 30 mg kg(-1)), although responses in normotensive airways to methacholine, but not to 5-HT, were enhanced. Antigen challenge of isolated lungs from actively sensitized rats elicited bronchoconstriction, not different between strains. Pretreatment with L-NAME increased the response to antigen challenge only in normotensive lungs. Compound 48/80 induced bronchoconstriction in lungs from either strain, equally. These responses to compound 48/80 were unaffected by L-NAME pretreatment. Thus, SHR airways lack relaxing factors and degranulation of mast cells in SHR lungs was not affected by endogenous NO.
Kwasniewski
Fábio H
FH
Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 2415, 05508-900 São Paulo, Brazil.
Landgraf
Richardt Gama
RG
Bakhle
Yeshwant S
YS
Jancar
Sonia
S
D000818:Animals; D016535:Bronchial Hyperreactivity / Q000503:physiopathology; D016084:Bronchoconstriction / Q000502:physiology*; D016085:Bronchoconstrictor Agents / Q000494:pharmacology; D015550:Cell Degranulation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006967:Hypersensitivity / Q000503:physiopathology; D066298:In Vitro Techniques; D008168:Lung / Q000502:physiology*; D008297:Male; D008407:Mast Cells / Q000187:drug effects / Q000502:physiology; D016210:Methacholine Chloride / Q000494:pharmacology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D010047:Ovalbumin / Q000276:immunology; D051381:Rats; D011918:Rats, Inbred SHR; D017208:Rats, Wistar; D003189:p-Methoxy-N-methylphenethylamine / Q000494:pharmacology
D016085:Bronchoconstrictor Agents; D004791:Enzyme Inhibitors; D016210:Methacholine Chloride; D009569:Nitric Oxide; D003189:p-Methoxy-N-methylphenethylamine; D010047:Ovalbumin; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester