• , • • \ SKELETAL MUSCLE METABOLISM AND PERFORMANCE DURING HEAVY MUSCULAR CONTRACTION IN THE ISOLATED PERFUSED RAT HINDQUARTER by LAWRENCE L. SPRIET, M.Sc • .A Thesis Submitted to the School of Gr'aduate Studies in Partial Fulfilment of the Requirements for theoegree Doctor of Philosophy McMaster University @JUly, 1984
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SKELETAL MUSCLE METABOLISM
AND PERFORMANCE DURING HEAVY
MUSCULAR CONTRACTION IN THE
ISOLATED PERFUSED RAT HINDQUARTER
by
LAWRENCE L. SPRIET, M.Sc •
.A Thesis
Submitted to the School of Gr'aduate Studiesin Partial Fulfilment of the Requirements
for theoegreeDoctor of Philosophy
McMaster University
@JUly, 1984
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MUSCLE METABOLISM AND PERFORMANCE DURING
HEAVY CONTRACTION
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DOCTOR DF PHILOSOPHY (1984)(Medical Science)
MCMASTER UNIVERSITYHamilton, Ontario
TITLE:
AUTHOR:
Skeletal Muscle Metabolism and Perform~ce
During Heavy Muscular Contraction in the'Isolated Perfused Rat Hindquarter '
Lawrence L. Spriet, B.Sc. (Waterloo university)
M.Sc. (York"University)
SUPERVISOR: Dr. N.L. Jones
NUMBER OF"PAGES: x, 226
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ABSTRACT
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Direct assessments of the relative contribut ions of•
th~ major energy releasing pathways in human skeletal muscle
during heavy exercise
invasive measurements
are difficult to obtain dpe to the..-....required. With an isolated muscle
,preparation the muscles' environment is carefully controlled
and all metabolic measurements are directly obtained. For
this reason the isolated perfused rat hindquarter model,
previously used to study resting muscle metabolism, was
developed to examine the metabolism and performance
heavily contracting skeletal muscle.
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Energy calculations based upon measurements of 02
uptake (aerobic metabolism), lactate product ion (anaerobic
glycolysis) and CP hydrolysis (alactic anaerobiosis) were
made during 20 minutes of repetitive tetanic stimulation.
During the initial 5 minut~s of stimulation isometric tension
production was high but fatigued rapidly and anaerobic
involvement in energy production was large (30%), especially
in the fast-twitch glycolytic muscle fibers. Muscle
glycogenolysis provided the majority of substrate for both
anaerobic glycolysis and aerobic metabolism. During the
final 15 minutes of stimulation aerobic metabolism dominated
(90%) while 60% of peak tension was held, mainly by the
I am extremely grateful to my supervisor, Dr. Norman~
L. Jones and my committee members, Dr. George J.F.
Heigenhauser and Dr. C.J. Toews for their assistance and
guidance during this project. The early work with this
hindquarter model by Gus Matsos and Sandra J. Peters and
their helpful discussions and technical expertise as
co-workers in the laboratory are great fully acknowledged.
The completion of this wo-rk is a tribute to my wife
Anne, for her undaunt ing support, understand ipg and Cassistance throughout the project.
This research was supported by the Medical Research
Council of Canada.
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TABLE OJ!' CONTENTS
Section
) Title Page
Descriptive Note
Abstract
ACkno(~,edgements
Table 'of Contents ,List of Figures,
"List of Tables
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vi
viii
x
43444445474849505354
) 6061
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1.1.11.21.31.4
1.,51.61. 6. 11. 6.21. 6.31. 6. 41. 6. 51. 6. 6
. 1. 71.8
1.9
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2.12.1.12.1. 22.1. 32.1.42.1. 52.22.32.42.52.6
HISTORICAL INTRODUCTION 1Introduction ' 1The Hill-Meyerhof Theory of Muscle Metabolism 3Phosphate Compounds in Muscle 4Additional Findings Contradicting the
Hill-Meyerhof Theory 7Summary 10Fuel Sources for Muscle Metabolism 11Early Research 11Circulating Free Fatty Acids 15Intramuscular Triacylglycerol' 19Circulat ing Glucose, 22Intramuscular Glycogen 25The Interaction of Fat and Carbohydrate
Fuels in Muscle 27 'Anaerobic Metabolism 30The Effects of Acidosis on Muscle Metabolism
and Performance 35Purpose of the Thesis 40
DEVELOPMENT OF THE ISOLATED PERFUSED RATHINPQUARTER MODEL
Early per-fusionsPerfusion ProtocolHindquarter PerformanceOxygen DeliveryNon-Recirculating Perfusion SystemCollection of Fresh Red Blood CellsPerfusion Related Alterations
• Surgical AlterationsHindquarter Stimulation and Performan~Measurement 'Related Improvement sSummary
MUSCLE METABOLISM AND PERFORMANCE DORINGHEAVY EXERCISE IN THE PERFOSED RATHINDQUARTER
IntroductionMethodsAnimalsPerfusion MediumHindquarter Surgical PreparationPerfusion ApparatusStimulation of Perfused Skeletal MuscleSampling of Perfused Skeletal MusclePerfusion ProtocolAnalytical MethodsStatisticsResul tsDiscussion
EFFECTS OF ACIDOSIS ON RAT MUSCLE METABOLISMAllD PERFORMAllCE DURING HEAVY EXERC ISE
IntroductionMethodsResul tsDiscussion
GENERAL SUMMARYIntroductionObservations and Conclusions of the ThesisQuestions for Future Repearch
APPENDICES.CalculationsOxygen Uptake CalculationsEnergy Release CalculationsTotal Oxygen UtilizedLactate ProducedCreatine Phosphate UtilizedGlycogen utilization and Glucose uptakeSummaryCa~culation of Contribution of Energy· .. Subst~ates for Aerobic Metabolism During
the Final 15 min of StimulationCharacterization Study Mean MU$cle DataCharacterization Study Individual DataAcidosis Study Mean Muscle Metabolite' DataAcidosis Study Individual Data'Rat Hindquarter Dye Perfusion Data
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6262636363646667697072767689
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102102103106122
lJ7137137141
145145145145145146148148149
149151156178186210
BIBLIOGRAPHY
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212-226
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LIST Ol!' l!'IGURES
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1 Contribution of major energy releasing pathwaysto tota energy supply ~ith exercise (Keulet al, 1 i!) 12
2 Tension prod tion by the rat hindquarte~'undervarying cond' ions and in previousinvestigations 46
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Rat hindquarter stabilization and tendonattachment
Rat hindquarter perf~sion apparatus
Perfusion protocol
Tensi9n generation by the ,hindquarter
Hindquarter oxygen uptake and perfusionpressure
Hindquarter lactate release and glucoseuptake
Hindquarter free fatty acid and glycerolrelease
Muscle glycogen and lactate concentrationsfollowing the perfusions
,Muscle CP and ATP concentrations followingthe perfusions
Muscle triacylglycerol con~ent before andafter 20 min of stimulation
Perfusion pressure during acidosis
Tension generation during acidosis
Oxygen uptake during acidosis
Lactate release during acidosis
GlucQse uptake during acidosis
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108
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~..Figure .~~
...18 Muscle glycogen utilization and lactate
accumulation following 5 min ofst~ulation during acidosis . 116
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Muscle CP and ATP concentra~ons following5 min of stimulation dqri~ acidosis
Muscle glycogen utilization and lactateaccumulation following 20 min of 'stimulation during acidosis
Muscle CP and ATP concentrations following20 min of.stimulation during acidosis
Relative lactate release from working muscleduring 5 min of stlmulation during acidosisand control conditions
Lactate release normalized for tensionproduction during acidosis and control
.. conditions
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Table
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LIST OF TABLES
~pmance variables at selected workloads
Effects'of fasting on muscle glycogen yont~nt
Characteristics of the perfusion mediums,Electroiyte ,data at rest and during
stimulationI
Energy released'during 20 min o~ stimulation
sources\and fa'tes of gll,lc~seduring.20minof sttmulation "....
p~ge
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77
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Energy released during acidotic stimulation
Contribution Of energy substrates to aerobicmetabolism ?,uring the fin'al 15.m'in ofstimulatio~