title: Sympathetic innervation of human tracheal and bronchial smooth muscle.
abstract: We have assessed functional and structural evidence for sympathetic innervation of human tracheal and bronchial smooth muscles. In the bronchus, functional evidence for such innervation was shown by the following results: a leftward shift in the noradrenaline inhibitory dose-response curve by the neuronal uptake blocker imipramine; the inhibition of uptake of 3H-L-noradrenaline by the neuronal uptake blockers imipramine, cocaine and phenoxybenzamine; and the induced release of noradrenaline and its metabolites by tyramine and electrical field stimulation using nerve-specific parameters; and selective inhibition of field-stimulated contractions by isoprenaline. Structural evidence was shown by the presence of small dense-cored vesicles containing nerve varicosities, occasionally in close proximity to morphologically characteristic cholinergic nerve-endings. This suggests the possibility of presynaptic modulation of acetylcholine release by noradrenaline.
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D001980:Bronchi / Q000187:drug effects / Q000294:innervation* / Q000502:physiology; D003000:Clonidine / Q000494:pharmacology; D004558:Electric Stimulation; D006801:Humans; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D009130:Muscle, Smooth / Q000187:drug effects / Q000294:innervation / Q000502:physiology; D009638:Norepinephrine / Q000008:administration & dosage / Q000378:metabolism; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D009435:Synaptic Transmission / Q000187:drug effects; D014132:Trachea / Q000187:drug effects / Q000294:innervation* / Q000502:physiology
chemical_list: D007545:Isoproterenol; D003000:Clonidine; D000109:Acetylcholine; D009638:Norepinephrine