Direct and reflex bronchoconstriction induced by histamine aerosol inhalation in dogs

摘要: Histamine aerosols were administered to nine anesthetized, paralyzed, mechanically ventilated mongrel dogs with the cervical vagi first intact, then sectioned, and peripherally stimulated at two intensities. Pulmonary resistance (RL) was measured, dose-response curves constructed in four conditions. All had dose-related increases RL increasing histamine aerosol concentrations. After cut, degree which constant levels of vagal stimulation altered relationships assessed by examining slopes positions vs. curves. Four animals studied showed evidence efferent activity as concentration increased, but three did not. Two equivocal responses that suggested not clearly demonstrated. These results indicate that, addition direct effects histamine, extent basis for interaction this stimulus varies among dogs. The suggest is related either (tone) or (reflexes).