Heat production by single fibres of frog muscle

1983 ◽  
Vol 4 (2) ◽  
pp. 207-222 ◽  
Author(s):  
N. A. Curtin ◽  
J. V. Howarth ◽  
R. C. Woledge
Keyword(s):  
Heat Production ◽  
Frog Muscle ◽  
Single Fibres

Scientific contributions of A. V. Hill: exercise physiology pioneer

2002 ◽  
Vol 93 (5) ◽  
pp. 1567-1582 ◽  
Author(s):  
David R. Bassett
Keyword(s):  
World War Ii ◽  
Heat Production ◽  
Time Course ◽  
Exercise Physiology ◽  
Frog Muscle ◽  
World War ◽  
Academic Assistance ◽  
Physiological Adaptations ◽  
Velocity Equation ◽  
Force Velocity

Beginning in 1910, A. V. Hill performed careful experiments on the time course of heat production in isolated frog muscle. His research paralleled that of the German biochemist Otto Meyerhof, who measured the changes in muscle glycogen and lactate during contractions and recovery. For their work in discovering the distinction between aerobic and anaerobic metabolism, Hill and Meyerhof were jointly awarded the 1922 Nobel Prize for Physiology or Medicine. Because of Hill's interest in athletics, he sought to apply the concepts discovered in isolated frog muscle to the exercising human. Hill and his colleagues made measurements of O2 consumption on themselves and other subjects running around an 85-m grass track. In the process of this work, they defined the terms “maximum O2 intake,” “O2requirement,” and “steady state of exercise.” Other contributions of Hill include his discoveries of heat production in nerve, the series elastic component, and the force-velocity equation in muscle. Around the time of World War II, Hill was a leading figure in the Academic Assistance Council, which helped Jewish scientists fleeing Nazi Germany to relocate in the West. He served as a member of the British Parliament from 1940 to 1945 and as a scientific advisor to India. Hill's vision and enthusiasm attracted many scientists to the field of exercise physiology, and he pointed the way toward many of the physiological adaptations that occur with physical training.

scholarly journals Titin switches from an extensible spring to a mechanical rectifier upon muscle activation

2021 ◽  
Author(s):  
Caterina Squarci ◽  
Pasquale Bianco ◽  
Massimo Reconditi ◽  
Marco Caremani ◽  
Theyencheri Narayanan ◽  
...  
Keyword(s):  
Thin Filament ◽  
Muscle Activation ◽  
Striated Muscle ◽  
Thick Filament ◽  
Frog Muscle ◽  
Motor Responses ◽  
Filament Activation ◽  
Single Fibres ◽  
Myosin Motors ◽  
Stimulation Of

In contracting striated muscle titin acts as a spring in parallel with the array of myosin motors in each half-sarcomere and could prevent the intrinsic instability of thousands of serially linked half-sarcomeres, if its stiffness, at physiological sarcomere lengths (SL), were ten times larger than reported. Here we define titin mechanical properties during tetanic stimulation of single fibres of frog muscle by suppressing myosin motor responses with Para-Nitro-Blebbistatin, which is able to freeze thick filament in the resting state. We discover that thin filament activation switches I-band titin spring from the large SL-dependent extensibility of the OFF-state to an ON-state in which titin acts as a SL-independent mechanical rectifier, allowing free shortening while opposing stretch with an effective stiffness 4 pN nm-1 per half-thick filament. In this way during contraction titin limits weak half-sarcomere elongation to a few % and, also, provides an efficient link for mechanosensing-based thick filament activation.

scholarly journals Initial Heat Production in Isometric Frog Muscle at 15°C

1973 ◽  
Vol 62 (3) ◽  
pp. 271-285 ◽  
Author(s):  
Allan Fraser ◽  
Francis D. Carlson
Keyword(s):  
Heat Production ◽  
Sarcomere Length ◽  
Heat Rate ◽  
Frog Muscle ◽  
Mechanical Activity ◽  
Sartorius Muscle ◽  
Cooling Phase ◽  
Frog Sartorius ◽  
Initial Heat ◽  
Rest Length

An infrared radiation-detecting system was used to measure initial heat production in bull frog sartorius muscle at 15°C. Numerous tests with the system showed that thermal artifacts were not noticeable. Many previous measurements with myothermic thermopiles were corroborated with this method. In addition, a cooling phase as large as 0.39 of peak exothermicity was found during and after relaxation. Cooling diminished with both increasing sarcomere length and increasing duration of mechanical activity. No large rapid increase in heat rate accompanied a 0.6 reactivation at the peak of twitch tension. Above rest length, initial heat rate and the heat produced up to the peak of tension decreased nearly proportionally with overlap of myofilaments, while the total twitch initial heat decreased slightly.

Heat production of sedimentary rocks in the Sichuan basin, Southwest China

2018 ◽  
Vol 52 (5) ◽  
pp. 401-413 ◽  
Author(s):  
Chuanqing Zhu ◽  
Ming Xu ◽  
Nansheng Qiu ◽  
Shengbiao Hu
Keyword(s):  
Heat Production ◽  
Sichuan Basin ◽  
Southwest China ◽  
Sedimentary Rocks ◽  
The Sichuan Basin
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