Biomaterial Database

The rate of changes in tension within fused tetani of single motor units in rat medial gastrocnemius muscle. 1998

J Celichowski, and E Bichler

Department of Neurobiology, University School of Physical Education, Poznań, Poland.

The time course of fused tetani of three main types of motor units: slow (S), fast resistant (FR) and fast fatigable (FF) was studied in the rat medial gastrocnemius. The rate of tension generation and of the relaxation within a tetanus was measured under isometric conditions. These measurements were performed at three points during both the contraction and relaxation: the beginning, the middle and the end of the phase of changes in tension. Significant differences were found in the rate of tension changes between fast and slow units. Comparison of FF and FR units showed less pronounced differences in their rates of the contraction and the relaxation. Moreover, slow units showed significantly greater slowing of both the contraction and relaxation within a tetanus in relation to the speed of their twitch when compared to fast motor units. The rate of changes in tetanic tension correlated to twitch time parameters and to tension generated during twitch or tetanus. The results point out that the well known difference in the speed of twitch contraction between fast and slow units is also visible in their fused tetani.

UI	MeSH Term	Description	Entries
D009119	Muscle Contraction	A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.	Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D017208	Rats, Wistar	A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.	Wistar Rat,Rat, Wistar,Wistar Rats
D051381	Rats	The common name for the genus Rattus.	Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus
D018482	Muscle, Skeletal	A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.	Anterior Tibial Muscle,Gastrocnemius Muscle,Muscle, Voluntary,Plantaris Muscle,Skeletal Muscle,Soleus Muscle,Muscle, Anterior Tibial,Muscle, Gastrocnemius,Muscle, Plantaris,Muscle, Soleus,Muscles, Skeletal,Muscles, Voluntary,Skeletal Muscles,Tibial Muscle, Anterior,Voluntary Muscle,Voluntary Muscles
D018656	Muscle Fibers, Fast-Twitch	Skeletal muscle fibers characterized by their expression of the Type II MYOSIN HEAVY CHAIN isoforms which have high ATPase activity and effect several other functional properties - shortening velocity, power output, rate of tension redevelopment. Several fast types have been identified.	Muscle Fibers, Intermediate,Muscle Fibers, Type II,Muscle Fibers, White,Fast-Twitch Muscle Fiber,Fast-Twitch Muscle Fibers,Fiber, Fast-Twitch Muscle,Fiber, Intermediate Muscle,Fiber, White Muscle,Fibers, Fast-Twitch Muscle,Fibers, Intermediate Muscle,Fibers, White Muscle,Intermediate Muscle Fiber,Intermediate Muscle Fibers,Muscle Fiber, Fast-Twitch,Muscle Fiber, Intermediate,Muscle Fiber, White,Muscle Fibers, Fast Twitch,White Muscle Fiber,White Muscle Fibers
D018657	Muscle Fibers, Slow-Twitch	Skeletal muscle fibers characterized by their expression of the Type I MYOSIN HEAVY CHAIN isoforms which have low ATPase activity and effect several other functional properties - shortening velocity, power output, rate of tension redevelopment.	Muscle Fibers, Red,Muscle Fibers, Type I,Fiber, Red Muscle,Fiber, Slow-Twitch Muscle,Fibers, Red Muscle,Fibers, Slow-Twitch Muscle,Muscle Fiber, Red,Muscle Fiber, Slow-Twitch,Muscle Fibers, Slow Twitch,Red Muscle Fiber,Red Muscle Fibers,Slow-Twitch Muscle Fiber,Slow-Twitch Muscle Fibers
D018763	Muscle Fatigue	A state arrived at through prolonged and strong contraction of a muscle. Studies in athletes during prolonged submaximal exercise have shown that muscle fatigue increases in almost direct proportion to the rate of muscle glycogen depletion. Muscle fatigue in short-term maximal exercise is associated with oxygen lack and an increased level of blood and muscle lactic acid, and an accompanying increase in hydrogen-ion concentration in the exercised muscle.	Fatigue, Muscle,Muscular Fatigue,Fatigue, Muscular