The Electrical and Mechanical Events of Neuro-Muscular Transmission in the Cockroach, Periplaneta Americana (L.)

1950 ◽  
Vol 27 (1) ◽  
pp. 1-13
Author(s):  
KENNETH D. ROEDER ◽  
ELIZABETH A. WEIANT
Keyword(s):  
Structural Changes ◽  
Periplaneta Americana ◽  
Mechanical Response ◽  
Motor Nerve ◽  
Potential Gradient ◽  
Positive Sign ◽  
Direct Stimulation ◽  
Bipolar Recording ◽  
Nerve Muscle ◽  
Muscle Potential

1. A nerve-muscle preparation in the metathorax of the cockroach is described. It consists of the second tergal muscle of the trochantin (muscle 162 of Carbonell) innervated by a branch of nerve 3 A. Electrical changes are recorded from electrodes on the muscle surface, and the onset of contraction is registered by the stylus of a piezo-electric pick-up. 2. With low (3-5 per sec.) stimulation rates at room temperature the neuromuscular delay is less than 1.2 msec., and the latent period of contraction about 3.0 msec. The muscle potential is 4-5 msec. in duration, positive in sign at the muscle surface, and monophasic in form with either monopolar or bipolar recording. During excitation a potential gradient develops along the muscle, the greatest positivity being in the middle near the point of nerve entry. 3. Neither electrical nor mechanical response show gradations with changes in stimulus strength or frequency. No facilitation is evident, and the response appears to be due to stimulation of a single quick motor nerve fibre. 4. In order to study the effects of direct stimulation nerve 3 was sectioned and allowed to degenerate. All trace of the peripheral nerve stump was lost after 3 days, when the muscle became completely inexcitable to all forms of electrical stimulation. There were no gross structural changes which would account for this loss of excitability. 5. It is concluded that the recorded muscle potential in the cockroach is analogous to the vertebrate end-plate potential, being the sum of local muscle potentials developing simultaneously in several fibres, and sequentially at several innervation points along the same fibre. Conduction within the muscle is carried out entirely by motor nerve fibres. 6. Possible causes of the positive sign of the muscle during activity are discussed.

scholarly journals The actions of eserine-like compounds upon frog’s nerve-muscle preparations, and the blocking of neuromuscular conduction

1940 ◽  
Vol 129 (856) ◽  
pp. 392-411 ◽  
Keyword(s):  
Neuromuscular Transmission ◽  
Motor Nerve ◽  
Calcium Content ◽  
Recovery Process ◽  
Direct Stimulation ◽  
Rate Of Recovery ◽  
Nerve Muscle ◽  
Minimum Interval ◽  
Site Of Stimulation ◽  
Stimulation Of

The actions of prostigmine, eserine, and the dimethylcarbamic ester of 8-hydroxymethylquinolinium methylsulphate upon the frog's isolated nervesartorius preparation have been examined by a method developed by Lucas (1911). With Ringer-soaked preparations from frogs kept at 14-18°C for some days before use the minimum interval at which two shocks applied to the nerve could elicit a summated muscular response was about 20% longer than the absolute refractory period of the nerve. Any of the above-mentioned compounds prolonged the minimum interval for a summated response, but caused the time at which an extra interpolated shock began to cut down the response to the final shock to become only a little later. Curarine or atropine reversed the prolongation of minimum interval. By the same method, the actions of the same eserine-like compounds upon preparations which had been treated with Ringer's solution of half the usual calcium content were examined. Either before or after treatment, it was impossible to cut down the muscular response by interpolating an extra shock. The action of prostigmine upon Ringer-soaked preparations was examined by a method developed by Adrian (1913), involving determination of the rate of recovery of excitability in the motor nerve at the site of stimulation and in the remaining more peripheral part of the preparation. Prostigmine influenced little the recovery process at the site of stimulation, whereas it prolonged the slower and more peripheral recovery process. Curarine reversed the prolongation of the more peripheral recovery. With Ringer-soaked preparations, during the block of neuromuscular transmission produced by rapid repetitive stimulation of the nerve, the response of the muscle to direct stimulation was reduced. If, however, neuromuscular transmission had been blocked by curarine, stimulation of the nerve did not reduce the response of the muscle to direct stimulation.

An Isolated Insect Ganglion-Nerve-Muscle Preparation

1966 ◽  
Vol 44 (3) ◽  
pp. 413-427
Author(s):  
GRAHAM HOYLE
Keyword(s):  
Motor Nerve ◽  
Output Frequency ◽  
Direct Stimulation ◽  
Mechanical Responses ◽  
Inhibitory Conditioning ◽  
Metathoracic Ganglion ◽  
Single Fibres ◽  
Preganglionic Stimulation ◽  
Nerve Muscle ◽  
Whole Muscle

1. A preparation is described which consists of an isolated locust metathoracic ganglion, together with one motor nerve and the skeletal muscle which it supplies (the anterior coxal adductor) in a state suitable for tension recording. 2. Mechanical responses were recorded from the whole muscle, or bundles of fibres and electrical responses of single fibres were recorded intracellularly. Some fibres were found in the muscle which have unusual properties. A single excitatory axon supplies the muscle. 3. Preganglionic stimulation applied to cut nerve trunks may excite an inhibitory-conditioning axon supplying the same muscle. 4. Direct stimulation of the motor nerve was combined with preganglionic stimulation in order to excite the two axons, and their interaction in relation to contraction of the muscle was studied. 5. The preparation shows spontaneous activity in the single excitatory axon supplying the muscle. 6. Various preganglionic stimulations were found to cause prolonged changes in the spontaneous motor output. By correlating the stimuli to the output in certain ways, long-lasting changes in mean output frequency were obtained. These may be regarded as a simple form of learning.

The Involvement of Nerves in the Epithelial Control of Crumpling Behaviour in a Hydrozoan Jellyfish

1981 ◽  
Vol 94 (1) ◽  
pp. 203-218 ◽  
Author(s):  
MICHAEL G. KING ◽  
ANDREW N. SPENCER
Keyword(s):  
Radial Nerve ◽  
Recording Electrode ◽  
Polyorchis Penicillatus ◽  
Nerve Bundles ◽  
Synaptic Junctions ◽  
Stimulating Electrodes ◽  
Nerve Muscle ◽  
Radial Muscle ◽  
Muscle Potential

1. The excitation pathways mediating the protective crumpling behaviour of Polyorchis penicillatus were studied with electrophysiological and ultrastructural techniques. 2. Stimulating the subumbrellar endoderm consistently resulted in a complex crumpling potential when recorded with suction electrodes from radial muscle (the prime effector). The potential represents the summation of a quick radial muscle potential (RMP) and a slow endodermal canal pulse (ECP). 3. The latencies of ECPs recorded from radial muscle during crumpling were directly proportional to the distance between the recording electrode and the subumbrellar stimulating electrode. Conversely, the latencies of RMPs, which were not tightly time-coupled to ECPs, were more directly related to the distance of the recording and stimulating electrodes from the marginal or apical termini of the radial muscle. 4. Stimulating the exumbrellar ectoderm resulted in a variable crumpling response, typically occurring after facilitation of numerous exumbrellar pulses (EPs). Since exumbrellar stimulation did not usually excite endoderm, the response recorded from radial muscle normally involved a simple RMP, un-associated with an ECP. 5. Typical synaptic junctions were observed between radial muscle processes and marginal neurites and between radial muscle and neurites of the radial nerve bundles along the length of the muscle. 6. The independence of the ECP and RMP conducting pathways demonstrates that endoderm does not provide the direct source of radial muscle excitation and the initiation of RMPs at points of known (marginal) and suspected (apical) nerve-muscle contact suggests the involvement of nerves in the control of crumpling behaviour. 7. These results are discussed in the light of other examples of active neuronal-epithelial interaction.

The Effect of Oxidation on the Mechanical Response of Isolated Elastin and Aorta

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
P. Mythravaruni ◽  
Parag Ravindran
Keyword(s):  
Experimental Data ◽  
Constitutive Model ◽  
Hydroxyl Radicals ◽  
Structural Changes ◽  
Mechanical Response ◽  
Uniaxial Extension ◽  
Mixture Theory

Oxidation of aorta by hydroxyl radicals produces structural changes in arterial proteins like elastin and collagen. This in turn results in change in the mechanical response of aorta. In this paper, a thermodynamically consistent constitutive model is developed within the framework of mixture theory, to describe the changes in aorta and isolated elastin with oxidation. The model is then studied under uniaxial extension using experimental data from literature.

Repair of Motor Nerve Defects: Comparison of Suture and Fibrin Adhesive Techniques

1989 ◽  
Vol 100 (1) ◽  
pp. 17-21 ◽  
Author(s):  
Shigeki Nishihira ◽  
Thomas V. McCaffrey
Keyword(s):  
Sciatic Nerve ◽  
Motor Nerve ◽  
Nerve Repair ◽  
Suture Technique ◽  
Nerve Graft ◽  
Tissue Adhesive ◽  
Muscle Twitch ◽  
Fibrin Adhesive ◽  
Fibrin Tissue Adhesive ◽  
Nerve Muscle

Two groups of rats were used to evaluate the results of nerve repair using fibrin tissue adhesive. In one group of 10 rats, a simple neurotomy of the sciatic nerve was performed. In the second group of 10 rats, a 1-cm segment of sciatic nerve was excised bilaterally and used as an autogenous nerve graft. The neurotomy and the nerve graft were repaired on one side by microsurgical suture technique using 10-0 nylon suture. The opposite side was repaired using fibrin adhesive. The results of the repair were assessed at 12 weeks. Functional assessment of nerve regeneration was performed in those rats with intact repair sites. Nerve-muscle twitch strengths were not significantly different ( p > 0.05) between nerves repaired using suture and fibrin adhesive; however, compound active potential parameters were significantly better in nerve grafts repaired using suture technique ( p < 0.05).

CONDUCTION BLOCK OF TERMINAL SOMATIC MOTOR FIBERS IN TICK PARALYSIS

1960 ◽  
Vol 38 (3) ◽  
pp. 287-295 ◽  
Author(s):  
Maurice F. Murnaghan
Keyword(s):  
Motor Nerve ◽  
Conduction Block ◽  
Nerve Impulse ◽  
Nerve Fibers ◽  
Treated Animal ◽  
Direct Stimulation ◽  
High Potassium ◽  
Control Value ◽  
Choline Acetylase ◽  
Stimulation Of

In the perfused anterior tibial muscle of the tick-paralyzed dog acetylcholine in excess of the control value is not liberated on stimulation of the peroneal nerve; in the normal muscle 7 μμg of acetylcholine is liberated per nerve volley. The paralysis is evidently not due to defective synthesis of acetylcholine because acetylcholine is liberated in control and high-potassium perfusates, the choline acetylase activity and the acetylcholine content of lumbar ventral roots and peroneal nerves do not differ from that in normal dogs, and the tick-paralyzed muscle differs from that in the hemicholinium-treated animal in its response to a train of nerve pulses after previous tetanization. As somatic motor nerve fibers in the paralyzed dog have previously been shown to conduct a nerve impulse and the factors required for acetylcholine release at the nerve terminal apparently are not absent in the paralyzed animal, the mechanism of the paralysis is probably due to an inability of the nerve impulse to traverse the terminal presynaptic fibers. The 'lesion' evidently extends to the end of the presynaptic fiber, i.e. more distally than in botulism, because direct stimulation of the tick-paralyzed muscle fails to liberate acetylcholine.

THE EFFECTS OF A CARDIAC GLYCOSIDE ON SUBCELLULAR STRUCTURES WITHIN NERVE CELLS AND THEIR PROCESSES IN SYMPATHETIC GANGLIA AND SKELETAL MUSCLE

1962 ◽  
Vol 40 (2) ◽  
pp. 303-315 ◽  
Author(s):  
R. I. Birks
Keyword(s):  
Skeletal Muscle ◽  
Structural Changes ◽  
Motor Nerve ◽  
Electron Microscopic Examination ◽  
Sympathetic Ganglia ◽  
Chloride Ions ◽  
Nerve Cells ◽  
Ion Concentration ◽  
Electron Microscopic ◽  
Pronounced Increase

Nerve cells and their processes in cat sympathetic ganglia and frog skeletal muscle have shown on electron microscopic examination alterations in subcellular morphology as a result of treatment with digoxin. Non-nervous cells were unaffected by the drug. These changes included, in ganglia, swelling of the affected cells, shrinkage of mitochondria with pronounced increase in internal density, swelling of Nissl substance in nerve cell bodies, and loss of structural detail in nerve processes. At the myoneural junction the motor nerve endings were swollen, mitochondria were altered, and the synaptic vesicles were reduced in numbers, those that remained being swollen. These changes were accompanied by invagination of the axon surface by Schwann cell processes.Cell swelling, but not the subcellular changes, was prevented by substitution of sulphate for chloride ions in the extracellular space. When the extracellular sodium ion concentration was reduced to 20 meq/l. the cells were completely protected against digoxin. It is concluded that swelling is caused by net uptake of sodium and chloride as a result of the known inhibitory action of digoxin on sodium extrusion by nerve cells. The possibility that these structural changes in subcellular organelles may be caused by a raised concentration of intracellular sodium ions, such as might occur during activity of excitable cells, is discussed.

The Croonian Lecture, 1967: The activation of striated muscle and its mechanical response

1971 ◽  
Vol 178 (1050) ◽  
pp. 1-27 ◽  
Keyword(s):  
Mechanical Response ◽  
Striated Muscle ◽  
Motor Nerve ◽  
Chemical Activation ◽  
Small Diameter ◽  
Trunk Muscles ◽  
Muscle Fibres ◽  
Minor Importance ◽  
Main Theme ◽  
Striated Muscles

Since the end of the 1939-45 war, the task of someone trying to understand muscular contraction has become in some respects easier, and in others more difficult. On the credit side, straightforward explanations are now available—and well established—for the main events in neuromuscular transmission, propagation of the action potential, the inward spread of an activating process, chemical activation of the myofibrils, and the sliding filament process of length change. On the other side new properties, new structures and new substances have turned up which cannot yet be fitted into any comprehensive scheme. Further, we are still totally in the dark about the actual molecular processes involved even in those steps for which clear explanations are available at the electrophysiological or electronmicroscopical level. Yet another complication is the extraordinary variety of muscle types that are being discovered, even among such thoroughly studied groups of animals as amphibians and mammals. I have been repeatedly struck by cases where the investigation of muscle has been held up by a false assumption based on the supposition that different kinds of contractile materials must work in the same way. For example, it has often been argued that smooth muscle and striated muscle are essentially similar, and therefore the striations are of only minor importance; this argument was given, for example, by Bernstein (1901, p. 284). The still more general argument that the nature of the ‘contractility’ of muscle should be looked for in the supposedly simpler processes of protoplasmic movement had been the main theme of a book by Verworn (1892). This attitude was, I am sure, one of the main reasons for the almost complete disregard of the striations by physiologists and biochemists between about 1910 and 1950. Again, the elucidation of the slow motor system of certain striated muscle fibres, present in probably all vertebrates, was delayed for many years by the discovery that in mammals even the slow postural activity of limb and trunk muscles is accompanied by propagated action potentials characteristic of fast motor systems. It was widely assumed on this basis that ‘tonic’ contractions in all vertebrate striated muscles consisted of asynchronous twitches or unfused tetani in scattered motor units, and most physiologists came to disregard the numerous indications—physiological and pharmacological (Langley 1913; Sommerkamp 1928; Wachholder & von Ledebur 1930) as well as histological (see Krüger (1952) for references both to his own work in the thirties and to other work)—of the existence of a second, slow, system in skeletal muscles of the frog. The very slow contractions elicited in the familiar gastrocnemius muscle of the frog by stimulating small-diameter motor-nerve fibres (Tasaki & Kano 1942; Tasaki & Mizutani 1944; Tasaki & Tsukagoshi 1944) came as a complete surprise to most physiologists, and received little attention until the matter was taken up by Kufiler and his colleagues (e.g. Kuffler & Vaughan Williams 1953). The astonishing range of structural diversity that becomes apparent when one looks at the arthropods as well as the vertebrates has recently been emphasized by Hoyle (1967).

A fragile seed of social and solidarity economy in post-disaster affected areas of Tohoku, Japan

2020 ◽  
Vol 31 (2) ◽  
pp. 97-114
Author(s):  
Fumihiko Saito
Keyword(s):  
Nuclear Power ◽  
Structural Changes ◽  
Positive Sign ◽  
Solidarity Economy ◽  
Root Cause ◽  
The North ◽  
North Eastern ◽  
Market Capitalism ◽  
Post Disaster

The world today faces a series of crises, and many observers have started to realize that the root cause of these crises is market capitalism. In such a context, the triple disasters of earthquake, tsunami, and nuclear power plant accident hit the north-eastern part of Japan on 11 March 2011. “3.11” has accelerated the long-term structural changes of rural Japan such as depopulation. Nine years since the disasters, one positive sign is the emergence of networks between producers and consumers who are now reciprocally connected. This article pays particular attention to a new monthly delivery package of magazine and food called, Tohoku Food Communication (TFC), first released in July 2013. The experiences of TFC can be interpreted as a fragile yet significant seed to promote social and solidarity economy (SSE). This paper critically examines both possibilities and limitations of SSE, which may contribute to making our society more sustainable than now. Keywords: “3.11”; natural disaster; Tohoku Food Communication (TFC); social and solidarity economy (SSE); sustainability.

scholarly journals Distribution of N-CAM in synaptic and extrasynaptic portions of developing and adult skeletal muscle.

1986 ◽  
Vol 102 (3) ◽  
pp. 716-730 ◽  
Author(s):  
J Covault ◽  
J R Sanes
Keyword(s):  
Schwann Cells ◽  
Motor Nerve ◽  
Cell Types ◽  
Nerve Terminals ◽  
Electron Microscopic ◽  
Adult Skeletal Muscle ◽  
Adult Rat ◽  
Embryonic Muscle ◽  
Nerve Muscle

Previous studies of denervated and cultured muscle have shown that the expression of the neural cell adhesion molecule (N-CAM) in muscle is regulated by the muscle's state of innervation and that N-CAM might mediate some developmentally important nerve-muscle interactions. As a first step in learning whether N-CAM might regulate or be regulated by nerve-muscle interactions during normal development, we have used light and electron microscopic immunohistochemical methods to study its distribution in embryonic, perinatal, and adult rat muscle. In embryonic muscle, N-CAM is uniformly present on the surface of myotubes and in intramuscular nerves; N-CAM is also present on myoblasts, both in vivo and in cultures of embryonic muscle. N-CAM is lost from the nerves as myelination proceeds, and from myotubes as they mature. The loss of N-CAM from extrasynaptic portions of the myotube is a complex process, comprising a rapid rearrangement as secondary myotubes form, a phase of decline late in embryogenesis, a transient reappearance perinatally, and a more gradual disappearance during the first two postnatal weeks. Throughout embryonic and perinatal life, N-CAM is present at similar levels in synaptic and extrasynaptic regions of the myotube surface. However, N-CAM becomes concentrated in synaptic regions postnatally: it is present in postsynaptic and perisynaptic areas of the muscle fiber, both on the surface and intracellularly (in T-tubules), but undetectable in portions of muscle fibers distant from synapses. In addition, N-CAM is present on the surfaces of motor nerve terminals and of Schwann cells that cap nerve terminals, but absent from myelinated portions of motor axons and from myelinating Schwann cells. Thus, in the adult, N-CAM is present in synaptic but not extrasynaptic portions of all three cell types that comprise the neuromuscular junction. The times and places at which N-CAM appears are consistent with its playing several distinct roles in myogenesis, synaptogenesis, and synaptic maintenance, including alignment of secondary along primary myotubes, early interactions of axons with myotubes, and adhesion of Schwann cells to nerve terminals.

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