Open AccessPrestretched airway smooth muscle response to length oscillation
Author(s) -
AlJumaily Ahmed M.,
Roos Kevin,
Bessaguet Sandy,
Jo Avila Miguel
Publication year - 2017
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.13076
Subject(s) - oscillation (cell signaling) , breathing , amplitude , physics , relaxation (psychology) , airway , respiratory system , biophysics , anatomy , medicine , chemistry , biology , optics , biochemistry , meteorology
Airway smooth muscle ( ASM ) hyperconstriction is the cause of many respiratory diseases including asthma. In vitro testing has demonstrated that the active forces of ASM are reduced by length oscillation ( LO ) mimicking tidal breathing. In a previous study, we demonstrated that this force reduction can be further enhanced when superimposing oscillations (with certain frequencies and amplitudes) on this LO . In contrast, it has been reported that pressurizing the lung may help in relieving asthmatic airway constrictions. Ultimately, this pressurizing stretches the ASM and may disturb the acto‐myosin cross‐bridges in a manner similar to LO ; however, it is of a static rather than dynamic nature. This research investigates the effect of combining both prestretch‐ and LO ‐applications on contracted porcine ASM . Isolated porcine ASM relaxation was tested with a 0.56%, 2%, or 4% stretch of its reference length ( L ref ) in addition to LO . These oscillations are composed of a main wave mimicking the normal breathing (frequency of 0.33 Hz and amplitude of 4% L ref ) and superimposed oscillations (frequencies of 20, 30, 40, 60 and 80 Hz and amplitude of 1% L ref ). The oscillations were maintained for 10 min. The results demonstrate that a prestretch of 0.56% and 2% L ref does enhance the contracted ASM relaxation at certain superimposed length oscillations frequencies while of 4% L ref does not.