The patency of the pharyngeal airway depends on pharyngeal cross-sectional area, compliance and shape. The extrinsic tongue muscles and the muscles of the pharyngeal wall play a major role in modulating these mechanical properties. The velopharynx appears to be the region most susceptible to collapse, and recent data suggest that compliance and the critical collapsing pressure (Pcrit) vary along the rostral-caudal extent of the velopharynx in humans and lower mammals. The rat pharynx will be isolated and pharyngeal pressure will be changed systematically while magnetic resonance images are obtained. Up to 15, 1.0 mm axial slices through the velopharynx and caudal oropharynx will be obtained, and the cross-sectional area of each slice computed. The pressure: area relation will then be obtained for each slice, which will allow derivation of regional pharyngeal compliance and Pcrit. The influence of pharyngeal muscle activity on these variables is evaluated by comparing control images with those obtained while the tongue or pharyngeal wall muscles are stimulated electrically. Geometric analyses will allow us to describe the ratio of the lateral to the anterior-posterior diameters of each axial slice (i.e., the """"""""ellipticity"""""""" of the airway), and the location of the flow-limiting segment (FLS) of the pharynx. The hypotheses are: 1) compliance is regionally dependent, with the highest values in the velopharynx; 2) the FLS is located in the velopharynx; 3) the shape of the velopharynx is most elliptical at the FLS; 4) activation of tongue or pharyngeal constrictor muscles will decrease regional compliance and Pcrit, and make the airway less elliptical (i.e., will """"""""stiffen"""""""" the airway). These experiments will provide unique information on the geometry and intrinsic mechanical properties of the pharynx, and the changes that occur with pharyngeal muscle contraction. The data may help to guide treatment strategies that are aimed at using airway pressure changes and/or implantable pharyngeal muscle nerve stimulators to alleviate airway obstruction during sleep.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
1R01HL068162-01A2
Application #
6579590
Study Section
Respiratory Physiology Study Section (RESP)
Program Officer
Twery, Michael
Project Start
2002-12-15
Project End
2005-11-30
Budget Start
2002-12-15
Budget End
2003-11-30
Support Year
1
Fiscal Year
2003
Total Cost
$293,370
Indirect Cost
Name
University of Arizona
Department
Physiology
Type
Schools of Medicine
DUNS #
806345617
City
Tucson
State
AZ
Country
United States
Zip Code
85721
Mehta, Puja K; Hermel, Melody; Nelson, Michael D et al. (2018) Mental stress peripheral vascular reactivity is elevated in women with coronary vascular dysfunction: Results from the NHLBI-sponsored Cardiac Autonomic Nervous System (CANS) study. Int J Cardiol 251:8-13
Wenger, Nanette K; Arnold, Anita; Bairey Merz, C Noel et al. (2018) Hypertension Across a Woman's Life Cycle. J Am Coll Cardiol 71:1797-1813
Sharma, Shilpa; Mehta, Puja K; Arsanjani, Reza et al. (2018) False-positive stress testing: Does endothelial vascular dysfunction contribute to ST-segment depression in women? A pilot study. Clin Cardiol 41:1044-1048
Nicholls, Stephen J; Tuzcu, E Murat; Wolski, Kathy et al. (2018) Extent of coronary atherosclerosis and arterial remodelling in women: the NHLBI-sponsored Women's Ischemia Syndrome Evaluation. Cardiovasc Diagn Ther 8:405-413
Wei, Janet; Bakir, May; Darounian, Navid et al. (2018) Myocardial Scar Is Prevalent and Associated With Subclinical Myocardial Dysfunction in Women With Suspected Ischemia But No Obstructive Coronary Artery Disease: From the Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction Study. Circulation 137:874-876
Elboudwarej, Omeed; Wei, Janet; Darouian, Navid et al. (2018) Maladaptive left ventricular remodeling in women: An analysis from the Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction study. Int J Cardiol 268:230-235
Humphries, K H; Izadnegahdar, M; Sedlak, T et al. (2017) Sex differences in cardiovascular disease - Impact on care and outcomes. Front Neuroendocrinol 46:46-70
Rambarat, Cecil A; Elgendy, Islam Y; Johnson, B Delia et al. (2017) Migraine Headache and Long-Term Cardiovascular Outcomes: An Extended Follow-Up of the Women's Ischemia Syndrome Evaluation. Am J Med 130:738-743
Birkeland, Kade; Khandwalla, Raj M; Kedan, Ilan et al. (2017) Daily Activity Measured With Wearable Technology as a Novel Measurement of Treatment Effect in Patients With Coronary Microvascular Dysfunction: Substudy of a Randomized Controlled Crossover Trial. JMIR Res Protoc 6:e255
Bairey Merz, C Noel; Pepine, Carl J; Walsh, Mary Norine et al. (2017) Ischemia and No Obstructive Coronary Artery Disease (INOCA): Developing Evidence-Based Therapies and Research Agenda for the Next Decade. Circulation 135:1075-1092

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