Role of nitric oxide on cholinergic component of bronchial tone in pig.
In vitro studies demonstrated that stimulation of intrinsic nerves of airway smooth muscle results in a predominantly contractile response, followed by a relaxant response which involves cholinergic, adrenergic and non-adrenergic non-cholinergic (NANC) nerve activation. Thus, in this paper it is determined whether endogenous nitric oxide (NO) modulates cholinergic neurotransmission in isolated pig airway smooth muscle. Bronchial rings were suspended in organ baths for isometric measurement of tension and the contractions were induced using electrical field stimulation (EFS) techniques. Then, the effects of L-NG-nitroarginine (L-NOARG, 10 microM), an inhibitor of NO synthase, and L-arginine (L-ARG, 1 mM), a precursor of NO synthesis, were evaluated. The cholinergic contractions induced by electrical field stimulation (EFS: 60 V, 2 ms, 60 Hz) of pig lobar bronchial preparations increased (29%) in the presence of L-NOARG (10 microM). This effect may be released by nerves in pig large airways during EFS.
Costantino
M
M
Institute of Pharmacology and Toxicology, 2nd University of Naples, Faculty of Medicine and Surgery, Italy.
Norel
X
X
Matera
M G
MG
Dulmet
E
E
Rossi
F
F
Brink
C
C
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001980:Bronchi / Q000187:drug effects / Q000294:innervation* / Q000502:physiology; D018680:Cholinergic Antagonists / Q000494:pharmacology; D004558:Electric Stimulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009129:Muscle Tonus / Q000187:drug effects / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects / Q000294:innervation* / Q000502:physiology; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D019335:Nitroarginine / Q000494:pharmacology; D010275:Parasympathetic Nervous System / Q000187:drug effects / Q000502:physiology*; D013552:Swine
D018680:Cholinergic Antagonists; D004791:Enzyme Inhibitors; D019335:Nitroarginine; D009569:Nitric Oxide; D001285:Atropine; D019001:Nitric Oxide Synthase