title: Responses of tracheobronchial receptors to halothane, enflurane, and isoflurane in anesthetized dogs.
abstract: We investigated the effects of halothane, enflurane, and isoflurane on the activity of 43 tracheobronchial slowly adapting stretch receptors (SARs) and 16 rapidly adapting irritant receptors (RARs) in 5 anesthetized, vagotomized, paralyzed, and artificially ventilated dogs. The 43 SARs were classified into 2 subtypes: (i) 17 low-threshold SARs with an expiratory discharge at FRC that were active throughout the respiratory cycle and (ii) 26 high-threshold SARs active only in inspiration. Ventilating the lungs with 5% of each anesthetic caused a significant increase in the inspiratory discharge of low-threshold SARs, whereas the expiratory discharge was inhibited or altogether silenced. While the activity of the majority of high-threshold SARs increased during the administration of the three volatile anesthetics, it decreased in those with a particularly high recruitment threshold. There was, however, a consistent increase in the pressure threshold at which all SARs were recruited. Ventilating the lungs with 5% of each anesthetic caused a significant decrease in activity of RARs. Our results indicate that all three halogenated anesthetics inhibit RARs at concentrations ranging from 1% to 5%.
authors.affiliation: Department of Physiology and Biophysics, University of Texas Medical Branch, Galveston 77555-0641.
authors.forename: T
authors.initials: T
authors.lastname: Nishino
authors.forename: J W
authors.initials: JW
authors.lastname: Anderson
authors.forename: G
authors.initials: G
authors.lastname: Sant'Ambrogio
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000758:Anesthesia; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001980:Bronchi / Q000187:drug effects / Q000378:metabolism*; D004285:Dogs; D004737:Enflurane / Q000494:pharmacology*; D005246:Feedback; D005260:Female; D006221:Halothane / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D007509:Irritants / Q000494:pharmacology; D007530:Isoflurane / Q000494:pharmacology*; D008297:Male; D011661:Pulmonary Stretch Receptors / Q000187:drug effects; D011955:Receptors, Drug / Q000187:drug effects*; D014132:Trachea / Q000187:drug effects / Q000378:metabolism*
chemical_list: D007509:Irritants; D011955:Receptors, Drug; D004737:Enflurane; D007530:Isoflurane; D006221:Halothane