title: Inhibitory mechanism of slowly adapting pulmonary stretch receptors after release from hyperinflation in anesthetized rabbits.
abstract: In anesthetized, artificially ventilated rabbits with vagus nerve section, release from 10 consecutive hyperinflations (inflation volume = 3 tidal volume) caused an inhibition of the slowly adapting pulmonary stretch receptor (SAR) activity for 16-22 sec. Intravenous administration of tetraethylammonium (TEA, 10 and 20 mg/kg), a K+ channel blocker, did not significantly alter either basal SAR discharge or tracheal pressure (PT). Although TEA treatment at 10.0 mg/kg had no significant effect on the magnitude and duration of inhibited SAR activity seen after release from hyperinflation, the increasing dose of this K+ channel blocker up to 20 mg/kg inhibited these effects of the receptor activity but this inhibition was small. The Na+ -K+ ATPase inhibitor ouabain (5 and 10 microg/kg) that had no significant effect on SAR activity and P(T) in the control abolished or attenuated the inhibitory action of SARs in a dose-dependent manner. Furthermore, the changes in dynamic lung compliance (Cdyn) and P(T) in response to post-hyperinflation were not significantly influenced by pretreatment with either TEA or ouabain. These results suggest that the inhibitory action of receptors seen during post-hyperinflation corresponded with the induction of slow afterhyperpolarization (sAHP), and that the mechanism of generating the sAHP of SARs is mainly mediated by the activation of Na+ -K+ pump activity.
authors.affiliation: Department of Physiology, Nippon Dental University, School of Dentistry at Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Matsumoto
authors.forename: M
authors.initials: M
authors.lastname: Ikeda
authors.forename: T
authors.initials: T
authors.lastname: Nishikawa
authors.forename: T
authors.initials: T
authors.lastname: Tanimoto
authors.forename: S
authors.initials: S
authors.lastname: Yoshida
authors.forename: C
authors.initials: C
authors.lastname: Saiki
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000502:physiology; D011661:Pulmonary Stretch Receptors / Q000502:physiology*; D011817:Rabbits; D012121:Respiration, Artificial; D019789:Tetraethylammonium / Q000494:pharmacology
chemical_list: D026902:Potassium Channel Blockers; D015221:Potassium Channels; D019789:Tetraethylammonium