In vivo and in vitro studies of the non-adrenergic non-cholinergic nervous system of the guinea-pig airways.
Functional studies indicate that the regulation of the tone in the guinea-pig airways in part involves non-adrenergic non-cholinergic (NANC) neural mechanisms. The characteristics of the relaxation induced by field stimulation of the non-adrenergic inhibitory neural system differed from those of the relaxation induced by purine derivatives. Furthermore, the presence of a maximally relaxant concentration of a purine or VIP did not affect the neurogenic inhibition. Thus, other transmitter candidates for the NANC inhibitory response than purines and VIP should be searched for. An atropine-resistant neurogenic bronchoconstriction was found to be abolished by capsaicin pretreatment. Capsaicin also reduced the lung content of substance P-like immunoreactivity. A tachykinin, possibly a neurokinin A-like peptide, has been considered to be the mediator of the NANC neural bronchoconstriction. Moreover, activation of NANC nerves may enhance airway microvascular permeability to macromolecules. Whether NANC nerves are involved in the neurogenic control of secretion from submucosal glands and of mucociliary clearance in guinea-pig airways remains to be shown.
D000818:Animals; D001341:Autonomic Nervous System / Q000502:physiology*; D001980:Bronchi / Q000502:physiology; D001993:Bronchodilator Agents / Q000494:pharmacology; D002923:Cilia / Q000502:physiology; D004558:Electric Stimulation; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008833:Microcirculation / Q000187:drug effects; D009474:Neurons / Q000502:physiology; D012137:Respiratory System / Q000098:blood supply / Q000294:innervation*
D001993:Bronchodilator Agents