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In vitro Measurements of Tracheal Constriction Using Mice
Published on: June 25, 2012
Tracheal vascular response to hypertonic and hypotonic solutions
J Prazma1, C C Coleman, W W Shockley
1Division of Otolaryngology/Head and Neck Surgery, University of North Carolina School of Medicine, Chapel Hill 27599-7070.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|June 1, 1994
Summary
Changes in airway surface osmolarity directly regulate upper airway mucosal blood vessel diameter. Hypertonic solutions cause dilation, while hypotonic solutions cause constriction, impacting air humidification.
Area of Science:
- Physiology
- Respiratory System Biology
- Vascular Biology
Background:
- The upper respiratory mucosa humidifies inhaled air, a process dependent on respiratory epithelium and blood vessels.
- Studying the in vivo relationship between airway surface and mucosal vasculature has been challenging.
Purpose of the Study:
- To investigate the impact of varying osmolarity on rat tracheal mucosal blood vessel diameter.
- To elucidate the regulatory mechanisms of mucosal blood flow in response to airway surface conditions.
Main Methods:
- Utilized a specialized chamber for direct in vivo visualization of rat tracheal microvasculature.
- Superfused the tracheal luminal surface with solutions of varying osmolarity (200, 290, 500 mosM) at 37°C.
- Measured changes in arteriole and venule diameters in response to hypo-, iso-, and hypertonic solutions.
Main Results:
- Mucosal vessels exhibited significant changes in diameter based on solution osmolarity.
- Arterioles (51 ± 5.6 μm) constricted by 10 ± 2.18 μm in hypotonic (200 mosM) and dilated by 11 ± 1.55 μm in hypertonic (500 mosM NaCl) solutions.
- Observed reversible constriction and dilation patterns in venules, with changes readily reversible upon return to isotonic conditions.
Conclusions:
- Tracheal epithelial exposure to altered osmolarity regulates mucosal blood vessel diameter.
- Changes in airway surface osmolarity serve as a key regulator for mucosal vascular tone, potentially influencing air humidification.
- Findings provide in vivo evidence for osmolarity-mediated control of upper airway microcirculation.
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