scholarly journals The Motor Innervation of a Triply Innervated Crustacean Muscle

1939 ◽  
Vol 16 (4) ◽  
pp. 398-402
Author(s):  
A. VAN HARREVELD
Keyword(s):  
Mechanical Injury ◽  
Muscle Fibres ◽  
Motor Innervation ◽  
Nerve Fibres ◽  
Crustacean Muscle ◽  
Conduction Process ◽  
Slow Contraction ◽  
Stimulation Of

The crustacean muscle is extremely sensitive to mechanical injury. This is due to the fact that the muscle fibres are innervated by a feltwork of nerve fibres which surrounds them. Apparéntly, there is a lack of a muscular conduction process in these muscles. Contractions have been observed in the same muscle fibres during stimulation of the axon for the fast contraction as well as during stimulation of the fibre for the slow contraction.

scholarly journals On the Excitation of Crustacean Muscle. I

1934 ◽  
Vol 11 (1) ◽  
pp. 11-27 ◽  
Author(s):  
C. F. A. PANTIN
Keyword(s):  
Latent Period ◽  
Good Condition ◽  
Carcinus Maenas ◽  
Muscle Fibres ◽  
Direct Stimulation ◽  
Contractile Mechanism ◽  
Crustacean Muscle ◽  
Slow Type ◽  
Slow Contraction ◽  
Stimulation Of

1. A brief account is given of the present position of the problem of neuromuscular action in the Crustacea. 2. A method is described by which the leg of Carcinus maenas may be perfused and stimulated. By this method the muscle remains in good condition for some 8 hours. 3. By stimulating the nerve in Carcinus leg with alternating currents of increasing intensity a series of varied responses is obtained. Above the threshold a contraction is developed of a comparatively slow type. With increase of intensity of the stimulus the response fails, owing to the excitation of inhibitory nerves. But at still greater intensities contraction reappears. This contraction, however, is very rapid. Tetani developed from the slow contraction are easily inhibited. Tetani developed from the rapid contraction cannot be inhibited by superimposed stimuli. 4. The relation of the quick and slow contractions is considered. It is not possible to fatigue one without fatiguing the other. Experiments show that on suddenly releasing the tension of the muscle during a tetanus, the tension always redevelops in a manner similar to the development of tension in the quick contraction, even though the tetanus be developed initially by the slow contraction. The same contractile mechanism is involved in both cases. 5. The latent period of contraction on stimulation of the nerve is very long, and ranges from 300σ at the threshold. That for direct stimulation of the muscle is 7-1Oσ. Above the threshold the latent period shortens rapidly with increasing stimulus. Over this region the contractions are of the slow type. The latent period becomes asymptotic to 50σ as the intensity is increased. At this value the contractions are of the quick type. Inhibition is effective where the latent period begins to approach its asymptotic value. 6. It is suggested that all the varied phenomena observed are related to the power of summation of crustacean muscle; that the slow contraction in response to a battery of stimuli is not due to a different contractile mechanism from the quick one, but that it is a summation effect by which a statistically increasing number of muscle fibres are brought into action as successive impulses pass down the nerve.

scholarly journals CHEMICAL CHANGES IN THE ADDUCTOR MUSCLE OF THE CHELIPED OF THE CRAYFISH IN RELATION TO THE DOUBLE MOTOR INNERVATION

1938 ◽  
Vol 22 (2) ◽  
pp. 193-206 ◽  
Author(s):  
W. R. Bergren ◽  
C. A. G. Wiersma
Keyword(s):  
Lactic Acid ◽  
Adductor Muscle ◽  
Mechanical Action ◽  
Phosphate Content ◽  
Motor Innervation ◽  
Chemical Changes ◽  
Maximum Extent ◽  
Mechanical Effects ◽  
Slow Contraction ◽  
Stimulation Of

An investigation has been made of the phosphate and lactic acid changes in the adductor muscle of the cheliped of the crayfish Cambarus clarkii upon stimulation of the isolated axons for the fast and slow contractions at determined frequencies. The data obtained point to the following conclusions: 1. When the mechanical effects of the two types of contraction are the same, the chemical changes are of the same order. If the mechanical effects are different, the chemical changes likewise are not equivalent. This is especially to be seen in the case of stimulation at 50 shocks per second: a slowly rising, long continued, strong slow contraction takes place with no apparent change in the phosphate content; a quickly rising fast contraction occurs with a large increase in the phosphate. 2. Since equivalent chemical changes accompany equivalent mechanical action, the two types of contraction do not differ in the essential mechanism of the chemical changes involved, and only one type of contractile substance is present. 3. Even when a contraction has taken place to the maximum extent obtainable, only enough phosphate is found to correspond to one-fifth to one-third of the available phosphagen.

The Functioning of the Giant Nerve Fibres of the Squid

1938 ◽  
Vol 15 (2) ◽  
pp. 170-185 ◽  
Author(s):  
J. Z. YOUNG
Keyword(s):  
Threshold Voltage ◽  
Functional Unit ◽  
Repetitive Firing ◽  
Maximal Response ◽  
Muscle Fibres ◽  
Nerve Fibres ◽  
Giant Fibre ◽  
Giant Fibres ◽  
Enormous Number ◽  
Stimulation Of

1. Stimulation of single giant nerve fibres in the stellar nerves of the squid (Loligo pealii) shows them to be motor axons which produce contraction of the circular fibres of the mantle muscles. 2. When a stellar nerve is stimulated with condenser discharges a maximal response is obtained at threshold voltage. No increase of response is obtained by further increase in the strength of stimulation except for an occasional slight increase at about ten times threshold voltage probably due to repetitive firing. It therefore appears that the stimulus produces a single impulse in the giant fibre, and that this is capable of exciting contraction in all the muscle fibres which it reaches. This confirms the conclusion reached on histological grounds that in spite of their syncytial nature each of the giant nerve fibres is a single functional unit. 3. Since there are about ten giant fibres on each side the mantle is divided into 20 neuromotor units, each nerve fibre innervating an enormous number of muscle fibres. The existence of these units can also very readily be demonstrated by the fact that threshold electrical stimulation at any point within the territory innervated by each single giant fibre sets up a contraction of the muscle fibres of all parts of the territory with which the stimulated area is in connexion through the nerve. 4. Stimulation of the smaller fibres in a stellar nerve after destruction of the giant fibre also causes contraction of the circular muscles of the mantle. The amount of this contraction increases progressively with increased voltage, presumably on account of the stimulation of more and more nerve fibres. The maximum tension developed in this way is always very much less than that produced by stimulation of the giant fibres. 5. The mantle is therefore provided with a double mechanism of expiratory contraction, maximal contractions being produced by single impulses in the giant fibres and graded contractions by those in the smaller fibres of the nerve. Presumably the former contractions are those involved in rapid movement, the latter in respiration. 6. There are also radial muscles, running through the thickness of the mantle, whose contractions effect the inspiration by making the cavity larger.

scholarly journals A Comparative Study Of The Double Motor Innervation In Marine Crustaceans

1938 ◽  
Vol 15 (1) ◽  
pp. 18-31
Author(s):  
C. A. G. WIERSMA ◽  
A. VAN HARREVELD
Keyword(s):  
Mechanical Response ◽  
Time Interval ◽  
Muscle Action ◽  
Motor Innervation ◽  
Action Current ◽  
Marine Crustaceans ◽  
First Case ◽  
Slow Contraction ◽  
Thick Fibre ◽  
Stimulation Of

A double motor innervation has been shown for several muscles of marine crustaceans. The adductors of the claws of Randallia and Blepharipoda and the adductor of the dactylopodite of the walking leg of Cancer were studied physiologically. The two motor axons which innervate these muscles have a different diameter (ratio 1.4: 1). Stimulation of the thick fibre causes a response, which, though it is not always faster than the response of the thin fibre, must be considered as a "fast" contraction. In Randallia and in Blepharipoda the slow contraction is higher than the fast with frequencies of less than ± 50 per sec., in Cancer with frequencies less than 100 per sec. The action currents of the two kinds of contraction are different. Both show facilitation, but under the same conditions of stimulation the fast-action currents are higher. The first stimulus of the thick fibre causes an action current top which is clearly distinguishable, the action currents of the slow contraction show up only after a number of stimuli. Even when the mechanical reaction on stimulation of the thick fibre is smaller than on similar stimulation of the thin fibre, the action currents are higher in the first case. A single impulse in the thick fibre does not cause a contraction, but sets up a muscle-action current. The chronaxie of this action current in Blepharipoda and Randallia is 0.8σ and is about the same as that found for the action current of the nerve. Two impulses in the thick fibre may cause a mechanical response, as is shown by summation experiments. The pseudo-chronaxie of this contraction was measured as 3.5 σ. The second action current shows facilitation, when it follows the first within 1 sec.; a mechanical reaction results with summation intervals of two stimuli of less than 10σ. The facilitation of the action current increases with decrease of the time interval between the two impulses; with the shortest intervals that give summation the resulting action current is a smooth high spike.

Cross-Innervation of the Thyroarytenoid Muscle by a Branch from the External Division of the Superior Laryngeal Nerve

1997 ◽  
Vol 106 (7) ◽  
pp. 594-598 ◽  
Author(s):  
Sina Nasri ◽  
Joel A. Sercarz ◽  
Pouneh Beizai ◽  
Young-Mo Kim ◽  
Ming Ye ◽  
...  
Keyword(s):  
Vocal Fold ◽  
Superior Laryngeal Nerve ◽  
Laryngeal Nerve ◽  
Spasmodic Dysphonia ◽  
Clinical Implications ◽  
Motor Innervation ◽  
Vocal Fold Vibration ◽  
Adductor Spasmodic Dysphonia ◽  
Thyroarytenoid Muscle ◽  
Stimulation Of

The neuroanatomy of the larynx was explored in seven dogs to assess whether there is motor innervation to the thyroarytenoid (TA) muscle from the external division of the superior laryngeal nerve (ExSLN). In 3 animals, such innervation was identified. Electrical stimulation of microelectrodes applied to the ExSLN resulted in contraction of the TA muscle, indicating that this nerve is motor in function. This was confirmed by electromyographic recordings from the TA muscle. Videolaryngostroboscopy revealed improvement in vocal fold vibration following stimulation of the ExSLN compared to without it. Previously, the TA muscle was thought to be innervated solely by the recurrent laryngeal nerve. This additional pathway from the ExSLN to the TA muscle may have important clinical implications in the treatment of neurologic laryngeal disorders such as adductor spasmodic dysphonia.

scholarly journals The interaction between two trains of impulses converging on the same motoneurone

1929 ◽  
Vol 105 (738) ◽  
pp. 363-371 ◽  
Keyword(s):  
Mechanical Effect ◽  
The Other ◽  
Muscle Fibres ◽  
Flexor Muscle ◽  
Afferent Pathways ◽  
Afferent Nerves ◽  
Maximal Stimulation ◽  
The Common ◽  
The Relationship ◽  
Stimulation Of

It was shown in an earlier paper (7) that if maximal stimulation of either of two different afferent nerves can reflexly excite fractions of a given flexor muscle, there are generally, within the aggregate of neurones which innervate that muscle, motoneurones which can be caused to discharge by either afferent (i. e., motoneurones common to both fractions). The relationship which two such afferents bear to a common motoneurone was shown, by the isometric method of recording contraction, to be such that the activation of one afferent, at a speed sufficient to cause a maximal motor tetanus when trans­mitted to the muscle fibres, caused exclusion of any added mechanical effect when the other afferent was excited concurrently. This default in mechanical effect was called “occlusion.” Occlusion may conceivably be due to total exclusion of the effect of one afferent pathway on the common motoneurone by the activity of the other; but facilitation of the effect of one path by the activation of the other when the stimuli were minimal suggests that, in some circumstances at least, the effect of each could augment and summate with th at of the other at the place of convergence of two afferent pathways. Further investigation, using the action currents of the muscle as indication of the nerve impulses discharged by the motoneurone units, has now given some information regarding the effect of impulses arriving at the locus of convergence by one afferent path when the unit common to both is already discharging in response to impulses arriving by the other afferent path. Our method has been to excite both afferent nerves in overlapping sequence by series of break shocks at a rapid rate and to examine the action currents of the resulting reflex for evidence of the appearance of the rhythm of the second series in the discharge caused by the first when the two series are both reaching the motoneurone.

The synaptic organization of optic afferents in the amphibian tectum

1974 ◽  
Vol 187 (1089) ◽  
pp. 421-447 ◽  
Keyword(s):  
Optic Nerve ◽  
Cell Layer ◽  
Maximum Amplitude ◽  
Synaptic Organization ◽  
Nerve Fibres ◽  
Synaptic Potentials ◽  
Postsynaptic Cell ◽  
Optic Fibre ◽  
Stimulation Of

Potentials in the amphibian tectum, evoked by stimulation of the optic nerve, were recorded extracellularly. Four discrete potentials, referred to as the m 1 , m 2 , u 1 and u 2 waves, occur at different latencies after stimulation. We have shown that these waves represent summed post-synaptic potentials generated by synchronous activation of four different groups of optic nerve fibres. The m 1 and m 2 waves are generated by two classes of myelinated optic nerve fibres, previously characterized as ‘dimming’ and ‘event’ fibres. The maximum amplitude of the m 2 wave occurs just below, and of the m 2 wave just above, cell layer 8 of P. Ramón. The u 1 and u 2 waves are generated by ‘edge’ and ‘convexity’ fibres, respectively. The maximum amplitude of the u 1 wave occurs near the surface of the tectum, and of the u 2 wave some 100 μm below it. Postsynaptic cell bodies for all four classes of optic fibre are located in layer 8.

scholarly journals VI. —Anaphylaxis and anaphylatoxins

1923 ◽  
Vol 211 (382-390) ◽  
pp. 273-315 ◽  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Guinea Pig ◽  
Anaphylactic Shock ◽  
The Body ◽  
Muscle Fibres ◽  
Direct Stimulation ◽  
Fundamental Conception ◽  
The Central Nervous System ◽  
Stimulation Of

In the study of the phenomena of anaphylaxis there are certain points on which some measure of agreement seems to have been attained. In the case of anaphylaxis to soluble proteins, with which alone we are directly concerned in this paper, the majority of investigators probably accept the view that the condition is due to the formation of an antibody of the precipitin type. Concerning the method, however, by which the presence of this antibody causes the specific sensitiveness, the means by which its interaction with the antibody produces the anaphylactic shock, there is a wide divergence of conception. Two main currents of speculation can be discerned. One view, historically rather the earlier, and first put forward by Besredka (1) attributes the anaphylactic condition to the location of the antibody in the body cells. There is not complete unanimity among adherents of this view as to the nature of the antibody concerned, or as to the class of cells containing it which are primarily affected in the anaphylactic shock. Besredka (2) himself has apparently not accepted the identification of the anaphylactic antibody with a precipitin, but regards it as belonging to a special class (sensibilisine). He also regards the cells of the central nervous system as those primarily involved in the anaphylactic shock in the guinea-pig. Others, including one of us (3), have found no adequate reason for rejecting the strong evidence in favour of the precipitin nature of the anaphylactic antibody, produced by Doerr and Russ (4), Weil (5), and others, and have accepted and confirmed the description of the rapid anaphylactic death in the guinea-pig as due to a direct stimulation of the plain-muscle fibres surrounding the bronchioles, causing valve-like obstruction of the lumen, and leading to asphyxia, with the characteristic fixed distension of the lungs, as first described by Auer and Lewis (6), and almost simultaneously by Biedl and Kraus (7). But the fundamental conception of anaphylaxis as due to cellular location of an antibody, and of the reaction as due to the union of antigen and antibody taking place in the protoplasm, is common to a number of workers who thus differ on details.

Motor innervation within supernumerary legs of cockroaches

1975 ◽  
Vol 63 (2) ◽  
pp. 497-503
Author(s):  
J. Westin ◽  
J. M. Camhi
Keyword(s):  
Motor Innervation ◽  
Stimulation Of

1. Clusters of legs having prothoracic and metathoracic origins were grown from the metathoracic coxa of the cockroach. 2. Or occasionally two, of the three major nerves innervating the cockroach leg. 3. Stimulation of a particular leg nerve (no. 3, 5 or 6) evoked movement at the same joints and in the same directions in a leg having only one nerve as in a normal leg. 4. Stimulation of a particular metathoracic nerve generally produced the same movements in a prothoracic leg transplanted to the metathoracic site as it did in a regenerated or intact metathoracic leg.

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