The Effects of Repetitive Stimulation on the Action Potential and the Twitch of Rat Muscle

Abstract

HANSON, J. T h e effects of repetitive stimulation on. the action potential and the twitch of rat muscle. Acta physiol. scand. 1974. 90. 387-400. Membrane potentials and contraction curves of different types of rat muscle fibre have been studied a t body and room temperatures with special regard to the effects of repetitive stimulation. Fast fibres (from the surface of the extensor muscles of the antebrachium) have a higher resting membrane potential, a higher amplitude and shorter duration of the spike of the action potential and a larger early negative after-potential than soleus fibres. I n the fast fibres stimu-B~R~N Y , M., ATPase activity of myosin correlated with speed of muscle shortening. A comparison between the effects of sympathomimetic amines on fast-and slow-contracting mammalian muscle. Brit. J. Pharma-BROWN, G. L. and U. S. VON EULER, The after-effects of a tetanus on mammalian muscle. units: Physiological-histochemical correlation in three types in cat gastrocnemius. Science CHAPMAN R. A., Experimental alteration of the relationship between the external calcium concentration and the contractile force generated by auricular trabeculae isolated from the heart of the frog, Rana pipiens. , Influence of temperature on isometric contractions of rat skeletal muscles. Nature (Lond.) 1968 a. 217. 1179-1 180. CLOSE, R. I. and J. F. Y . HOH, The after-effects of repetitive stimulation on the isometric twitch contraction of rat fast skeletal muscle. J. Physiol. (Lond.) 1968 b. 197. 4 6 1 4 7 7 .CONNOLLY, R., W. GOUGH and S. WINEGRAD, Characteristics of the isometric twitch of skeletal muscle immediately after a tetanus.

Increased sodium pump activity following repetitive stimulation of rat soleus muscles.

“…One explanation for this early enhancement of the M-wave would be that the resting and action potentials of individual muscle fibres increase during muscle activity but this suggestion has not been supported by the results of previous studies in animal muscles. Thus, it has been a general finding that the resting and action potentials of mammalian skeletal muscle fibres decrease following repetitive A. HICKS AND A. J. McCOMAS stimulation (for example, Locke & Solomon, 1967;Hanson, 1974;Juel, 1986), presumably as a result of the rise in interstitial [K+] associated with impulse activity (Hnik, Holas, Krekule, Kriz, Mejsnar, Smiesko, Ujec & Vyskocil, 1976;Juel, 1986). These results are not conclusive, however, since most of the animal experiments have been conducted in vitro, using bathing media likely to cause partial depolarization of muscle fibres with a concomitant rise in intracellular tNa+] (Creese & Northover, 1961;Kernan, 1963).…”

“…Hanson, 1974;Juel, 1986), to an absence of protein in the artificial bathing media. It was shown by Kernan (1963) that the resting potentials of rat muscle fibres in vitro corresponded to EK if plasma proteins were present in the bathing fluid; if they were absent the mean resting potential was 12-4 mV lower.…”

Calculation and registration of the same motor unit action potential

“…A: a picture of the intracellular action potential Vi(z) and its first and second derivatives. The Vi(z) represents the intracellular action potential during the propagation phase of an EDL muscle fibre of the rat (derived from Hanson 1974) as a function of the longitudinal position z (the conduction velocity used to transform the results of Hanson from the time to the distance domain is 3.2 m/sec). B: a schematic representation of the intracellular action potential and its first and second derivatives as they are related to the tripole model of Rosenfalck (1969).…”

“…Data of intracellular potentials V~n as found in the literature (Muschol| 1957;Yonemura 1967;Hanson 1974;Ludin 1976) were used to obtain the tripole parameters I1, I2 and L~. In order to deduce these param-eters photographic enlargements of Vi, registrations were used.…”

Proposta e análise de indicadores eletromiográficos espectrais e temporais em protocolos dinâmicos com indução de fadiga muscular localizada

“…Verificaram não haver correlação significativa entre velocidade de condução e o diâmetro das fibras. As membranas destas fibras apresentam maior potencial de repouso e potenciais de ação com maior amplitude e menor duração em comparação com as fibras do tipo I (contração lenta) (Hanson, 1974). Assim, a correlação entre velocidade de condução e composição das fibras pode ser atribuída às diferenças na excitabilidade das membranas das fibras dos tipos I e II.…”