The after effects of a tetanus on mammalian muscle

Abstract

Two accounts have recently appeared of the effects of an interpolated tetanus on the response of striated muscle to a series of regularly spaced, single motor-nerve volleys. Rosenblueth & Morison [1937] have recorded increases in twitch response as a result of tetani and a relief of partial curarization by the same means. Guttman and others [1937] have made similar observations on frog's muscle, and have concluded that the phenomenon is due to peripheral accumulation of a chemical mediator, which might be "acetylcholine or adrenine". As R o senblueth and M oris o n point out, the long duration of the effects makes it improbable that acetylcholine should, in the mammal, be responsible for them, and they suggest that a mobilization of potassium ions offers a more reasonable explanation of the phenomenon.In the present paper, the phenomenon of enhancement of twitch tension by a tetanus has been examined in detail, and evidence is advanced that it is due in part, at least, to potassium mobilization in the muscle fibre, and that the neuromuscular transmitting apparatus is not necessarily directly involved. METHODSCats decerebrated under preliminary ether aneesthesia were used in the great majority of the experiments. A few were done under chloralose aneasthesia, but we are under the impression that anaesthetics interfere to some extent with the phenomena under investigation.Gastrocnemius, soleus and tibialis anterior have been chosen for recording. The tension was recorded by either a Sherrington torsion-wire myograph or a flat-spring myograph of similar characteristics. The methods used for close arterial injections have already been described 1 Fellow of the Rockefeller Foundation.

Neuro‐muscular conduction in the fowl

“…As might be expected, from its effects in the mammal [Brown, 1938], curarine, in doses insufficient completely to block neuro-muscular conduction, greatly exaggerates the disparity between the action potential responses to a pair of nerve volleys. Thus, in one experiment, on the flexor perforatus muscle, the second action potential of a pair set up 10 msec.…”

“…The phenomenon of the augmented second action potential has been observed by Samoj loff [1908] and by Adrian & Lucas [1912] in freshly isolated frog's muscle, stimulated through its nerve, and it appears to differ only in its time relations from the effects we have observed. In the fowl, as in the frog [Bremer, 1927], the effect is greatly exaggerated by small doses of curarine, the use of which substance is necessary in the mammal to elicit the effect at all [Brown, 1938].…”

“…The effect of a tetanic stimulation in producing a longer increase in end-plate excitability, causing the first response to a post-tetanic volley to approach maximality, is obviously very closely allied to the relief of a partial curare paralysis by a similar tetanus [Boyd, 1932;Brown & Euler, 1938].…”

Post‐tetanic and drug‐induced repetitive firing in the soleus muscle of the cat

“…This type of post-tetanic augmentation, which has been attributed to an action on the motor nerve endings, is not evident in fast-contracting mammalian muscles such as the gastrocnemius or tibialis anterior. In the latter muscles, the post-tetanic increase in contractions is not associated with repetitive firing (Brown & von Euler, 1938 ;Feng et al, 1939 ;Bowman, Goldberg & Raper, 1962;Standaert, 1964) and has been ascribed to an action on the muscle fibres through which contractility is increased. Even in the soleus muscle of the cat, post-tetanic repetitive responses are not produced unless prolonged tetani of high frequency are applied.…”

Effects of twitch train on the tetanic contractility of the frog skeletal muscle.

“…Post-tetanic potentiation, a twitch augmentation caused by tetanic stimuli, can be regarded as an after-effect of repetitive stimuli with far higher frequencies. The phenomenon is neither the result of recruitment of muscle fibers since it is not influenced by the conditions of stimulation, namely indirect via nerve or direct (BROWN and VON EULER, 1938), nor could it be due to increased stiffness of the series-elastic component (CLOSE, 1972).…”