ERA

Download the full-sized PDF of The Effect of Dopamine on Pulmonary Diffusing Capacity and Capillary Blood Volume Responses to ExerciseDownload the full-sized PDF

Analytics

Share

Permanent link (DOI): https://doi.org/10.7939/R3K35MT5P

Download

Export to: EndNote  |  Zotero  |  Mendeley

Communities

This file is in the following communities:

Graduate Studies and Research, Faculty of

Collections

This file is in the following collections:

Theses and Dissertations

The Effect of Dopamine on Pulmonary Diffusing Capacity and Capillary Blood Volume Responses to Exercise Open Access

Descriptions

Other title
Subject/Keyword
Pulmonary capillary blood volume
Exercise tolerance
Dopamine blockade
Dopamine
Pulmonary diffusing capacity
Diffusing membrane capacity
Type of item
Thesis
Degree grantor
University of Alberta
Author or creator
Michaelchuk, Wade W
Supervisor and department
Stickland, Michael (Medicine and Dentistry)
Examining committee member and department
Boulé, Normand (Physical Education and Recreation)
van Diepen, Sean (Medicine and Dentistry)
Department
Physical Education and Recreation
Specialization

Date accepted
2017-09-28T10:16:26Z
Graduation date
2017-11:Fall 2017
Degree
Master of Science
Degree level
Master's
Abstract
Pulmonary diffusing capacity increases during exercise to meet the increasing oxygen (O2) demand of the body. Expansion of pulmonary capillary blood volume (Vc) and diffusing membrane capacity (Dm) are important contributors to the increased diffusing capacity observed during upright cycle exercise. Recent studies have shown that circulating dopamine, a pulmonary vascular vasodilator, may play an active role in Vc regulation through changes in pulmonary vascular tone. Subsequently, these changes may be responsible for the reduction in exercise tolerance seen during heavy exercise with dopamine receptor blockade. Thus, the purpose of this study was to examine the effect of exogenous dopamine as well as dopamine receptor-2 (D2-receptor) blockade on pulmonary diffusing capacity (DLCO), Vc, and Dm at baseline and during upright cycle exercise. Additionally, the effect of dopamine and D2-reeceptor blockade on time-to-exhaustion during heavy cycle exercise at 85% of VO2peak was assessed. Based on previous work, it was hypothesized that dopamine would increase DLCO, Vc, Dm, and exercise tolerance, while D2-receptor blockade would decrease DLCO, Vc, Dm, and exercise tolerance. Hemoglobin adjusted DLCO, Vc, and Dm were determined at rest and during exercise in 14 young, healthy, recreationally active, non-smoking subjects (VO2peak 45.8 ± 6.6 mL ∙ kg-1 ∙ min-1) using the Roughton and Forster (1957) multiple FIO2-DLCO method. Dependent variables were evaluated at baseline, as well as cycling at 60 and 85% of VO2peak under the following randomly assigned conditions: 1) intravenous saline and a placebo pill, 2) intravenous dopamine (2 µg ∙ kg-1 ∙ min-1) and a placebo pill, 3) intravenous saline and an oral D2-receptor antagonist (20 mg metoclopramide). The effect of dopamine on cycle time-to-exhaustion at 85% of VO2peak was also examined in the three conditions. Exogenous dopamine and dopamine blockade had no effect on DLCO, Vc, and Dm at baseline or at any intensity of exercise. Blockade reduced time-to-exhaustion (blockade, 259 ± 120 seconds; placebo, 367 ± 198 seconds; P<0.05), but intravenous dopamine did not improve time-to-exhaustion. Overall, dopamine does not appear to be important in the regulation of DLCO, Vc, and Dm at rest or during exercise. While endogenous dopamine appears to be important for the maintenance of time-to-exhaustion, providing exogenous dopamine does not appear to enhance exercise tolerance.
Language
English
DOI
doi:10.7939/R3K35MT5P
Rights
This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for the purpose of private, scholarly or scientific research. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
Citation for previous publication

File Details

Date Uploaded
Date Modified
2017-09-28T16:16:26.534+00:00
Audit Status
Audits have not yet been run on this file.
Characterization
File format: pdf (PDF/A)
Mime type: application/pdf
File size: 2201670
Last modified: 2017:11:08 17:18:16-07:00
Filename: Michaelchuk_Wade_W_201709_MSc.pdf
Original checksum: 343f3b3702b272b14b6c84546479a998
Activity of users you follow
User Activity Date