eTheses Repository

The effects of muscle mechanoreflex stimulation via passive muscle stretch on baroreflex function in humans

Drew, Rachel (2008)
Ph.D. thesis, University of Birmingham.

Loading
PDF (1132Kb)

Abstract

Human cardiovascular control during exercise is regulated by central command, muscle mechanoreflex stimulation and muscle metaboreflex activation. The muscle mechanoreflex can be stimulated by passive muscle stretch, which causes cardiovascular responses. However, the influence of passive stretch-induced muscle mechanoreflex stimulation on the baroreflex is unknown. Therefore, this thesis investigated the effects of muscle mechanoreflex stimulation via passive calf muscle stretch on baroreflex function in humans. Firstly, spontaneous baroreflex sensitivity decreases progressively during isometric exercise of increasing intensity. A concomitant rightward resetting of the baroreflex occurs, which shifts further rightward as exercise intensity increases. Secondly, muscle mechanoreflex stimulation by passive calf muscle stretch decreases spontaneous baroreflex sensitivity at rest, and during graded levels of local metabolite accumulation following isometric exercise of increasing intensity. Thirdly, muscle mechanoreflex stimulation by passive calf muscle stretch during concurrent local metabolite accumulation decreases the maximal gain of the function curve for carotid baroreflex control of heart rate, but not blood pressure. Overall, these findings suggest that muscle mechanoreflex stimulation via passive muscle stretch decreases baroreflex sensitivity via cardiac vagal inhibition, likely by modulating inputs at central integration sites. Also, metabolite sensitisation of stretch-sensitive muscle mechanoreceptive afferents is implied, which augments this cardiac vagal inhibition.

Type of Work:Ph.D. thesis.
Supervisor(s):White, Michael
School/Faculty:Colleges (2008 onwards) > College of Life & Environmental Sciences
Department:Sport and Exercise Science
Keywords:Mechanoreflex, stretch, baroreflex
Subjects:QP Physiology
Institution:University of Birmingham
Library Catalogue:Check for printed version of this thesis
ID Code:147
This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder.
Export Reference As : ASCII + BibTeX + Dublin Core + EndNote + HTML + METS + MODS + OpenURL Object + Reference Manager + Refer + RefWorks
Share this item :
QR Code for this page

Repository Staff Only: item control page