Innervation of the ventral diaphragm of the locust (Locusta migratoria)

1977 ◽  
Vol 69 (1) ◽  
pp. 23-32
Author(s):  
M. Peters
Keyword(s):  
Electrical Stimulation ◽  
Electrical Properties ◽  
Electrical Activity ◽  
Neuromuscular Junctions ◽  
Motor Nerve ◽  
Locusta Migratoria ◽  
Posterior Segment ◽  
Muscle Fibres ◽  
Inspiratory Muscles ◽  
Motor Neurones

1. Innervation and some electrical properties of the locust ventral diaphragm were investigated with electrophysiological and histological methods. 2. Muscle fibres are coupled electrically. Electrical stimulation evokes a graded active membrane response. 3. Each segment is innervated by four motor neurones as follows. Two motor neurones are situated in each abdominal ganglion. Branches of their axons supply the ventral diaphragm in the respective and the next posterior segment. 4. This pattern of innervation was confirmed by axonal Co and Ni staining of the motor nerve endings. 5. Neuromuscular junctions are excitatory. EPSPs show summation but no facilitation. 6. Spontaneous electrical activity of the diaphragm is to a certain degree coupled to activity of the main inspiratory muscles.

Comparison of slow larval and fast adult muscle innervated by the same motor neurone

1980 ◽  
Vol 84 (1) ◽  
pp. 103-118
Author(s):  
M. B. Rheuben ◽  
A. E. Kammer
Keyword(s):  
Developmental Stages ◽  
Neuromuscular Junctions ◽  
Motor Nerve ◽  
Thick Filament ◽  
Motor Neurone ◽  
Muscle Fibre Types ◽  
Thin Filaments ◽  
Adult Muscle ◽  
Motor Neurones ◽  
Two Stages

1. Muscles innervated by an identified set of motor neurones were compared between larval and adult stages. 2. The structure of the larval muscle is typically tonic: long sarcomeres, irregular Z-bands, and 10-12 thin filaments around each thick filament. The structure of the adult muscle is phasic: 3-4 micrometers sarcomeres, regular Z-bands, 6-8 thin filaments around each thick filament, and large mitochondrial volume. 3. The tensions produced by these muscles were correspondingly different. The larval twitch was about 7 times slower and the tetanus/twitch ratio 10 times greater than those of the adult. 4. No structural or physiological differences were observed in the neuromuscular junctions of the two stages. 5. The relatively unchanging functional relationship of a single motor neurone with two different muscle fibre types during two developmental stages is compared with the converse situation in which it has been reported that implantation of a different type of motor nerve into a muscle modifies contractile properties.

Zinc iodide-osmium tetroxide reaction: its effect on the synaptic vesicles in locust neuromuscular junctions and its chemical basis

1978 ◽  
Vol 36 (2) ◽  
pp. 614-615
Author(s):  
M. Reinecke ◽  
Ch. Walther
Keyword(s):  
Synaptic Vesicles ◽  
Osmium Tetroxide ◽  
Neuromuscular Junctions ◽  
Motor Nerve ◽  
Locusta Migratoria ◽  
Nerve Terminals ◽  
Neurobiological Research ◽  
Zinc Iodide ◽  
Electron Lucent

The zinc iodide-osmium tetroxide reaction (ZIO) was first used in neurobiological research by Maillet (Bull. Ass. Anat. 53, 233; 1968). Subsequently several authors have shown that, under appropriate conditions, ZIO stains mainly the interior of synaptic vesicles. The substrate of this reaction is under discussion, since ZIO can also react with other subcellular structures in a variety of tissues, e. g. mitochondria, endoplasmic reticulum, dictyosomes and lysosomes. Additionally, in vitro substances as different as some aminoacids, catecholamines, aldehydes and phospholipids (Pellegrino de Iraldi, Experientia 33, 1; 1977) can yield black precipitations with ZIO.Our studies were done with the motor nerve terminals at the femoral retractor unguis muscle of the locust (Locusta migratoria). These terminals are chiefly the endings of excitatory motoraxons and are characterized by the presence of electron lucent vesicles and by an accumulation of mitochondria.

The Action of Iontophoretically Applied Glutamate on Insect Muscle Fibres

1968 ◽  
Vol 49 (1) ◽  
pp. 83-93
Author(s):  
R. BERÁNEK ◽  
P. L. MILLER
Keyword(s):  
Equilibrium Point ◽  
Neuromuscular Junctions ◽  
Schistocerca Gregaria ◽  
Locusta Migratoria ◽  
Extracellular Recording ◽  
Fibre Surface ◽  
Adductor Muscle ◽  
Muscle Fibres ◽  
Glass Capillary ◽  
Insect Muscle

1. Electrophoretic application of L-glutamate from glass capillary micro-pipettes was used to investigate the ‘spot sensitivity’ of the membrane of coxal adductor muscle fibres from adult specimens of Schistocerca gregaria Forskål and Locusta migratoria (L.). 2. Circumscribed spots could be detected on the fibre surface where brief applications of L-glutamate produced transient depolarizations (glutamate potentials). 3. Extracellular recording of excitatory junction potentials revealed that focal points of glutamate sensitivity are closely related to, and probably identical with, neuromuscular junctions. 4. Large doses readily de-sensitized the membrane to L-glutamate for periods greatly exceeding the duration of the glutamate potentials. 5. In chronically denervated muscles peaks of sensitivity could still be detected. 6. Spots sensitive to L-glutamate were not depolarized by D-glutamate. 7. The equilibrium point for glutamate potentials coincides with the equilibrium point of miniature excitatory potentials and lies between -10 and -25 mV.

Colonial behaviour and electrical activity in the Hexacorallia

1975 ◽  
Vol 190 (1099) ◽  
pp. 239-256 ◽  
Keyword(s):  
Electrical Stimulation ◽  
Electrical Activity ◽  
Neuromuscular Junctions ◽  
Electrical Potential ◽  
Pulse Frequency ◽  
Mechanical Stimulus ◽  
Time Interval ◽  
Short Time Interval ◽  
Sea Anemones ◽  
Nerve Net

The behaviour of the polyps of eight coral species in the subclass Hexacorallia is described with reference to electrical activity recorded with extracellular suction electrodes. Following repetitive mechanical or electrical stimulation, waves of polyp retraction spread over the colony from the point of stimulation. In response to a single electrical or mechanical stimulus, a single electrical potential was evoked. It is suggested that this pulse represented activity in the colonial nerve net. The pulse was conducted without decrement over large areas of the colony. The conduction velocity was 15-25 cm s -1 at 25°C. There was no evidence for multiple firing following single threshold stimuli. Polyp retraction only occurred after two or more ‘nerve net' pulses had impinged upon the neuromuscular junctions of the retractor muscles within a short time interval. Colonial polyp retraction responses occurred, therefore, when a number of nerve net pulses were conducted across the colonial nerve net. A burst of pulses showed a reduction in frequency as it was conducted from the point of stimulation. A new explanation of colonial polyp retraction patterns in response to electrical stimulation is proposed. The different patterns may be explained in terms of the way in which the frequency (but not the number) of the pulses in a burst of nerve net activity changes with the distance conducted. Changes in nerve net pulse frequency affect the degree of facilitation of the neuromuscular junctions which, in turn, affects the size of the muscle contraction evoked. The possibility is considered that ‘slow conduction systems’ similar to those found in sea anemones may also be present in the colonial Hexacorallia.

Linear electrical properties of striated muscle fibres observed with intracellular electrodes

1964 ◽  
Vol 160 (978) ◽  
pp. 69-123 ◽  
Keyword(s):  
Electrical Properties ◽  
Striated Muscle ◽  
Surface Membrane ◽  
Fibre Surface ◽  
Step Function ◽  
Muscle Fibres ◽  
Appreciable Effect ◽  
Current Application ◽  
Current Path ◽  
Wide Range

The linear electrical properties of muscle fibres have been examined using intracellular electrodes for a. c. measurements and analyzing observations on the basis of cable theory. The measurements have covered the frequency range 1 c/s to 10 kc/s. Comparison of the theory for the circular cylindrical fibre with that for the ideal, one-dimensional cable indicates that, under the conditions of the experiments, no serious error would be introduced in the analysis by the geometrical idealization. The impedance locus for frog sartorius and crayfish limb muscle fibres deviates over a wide range of frequencies from that expected for a simple model in which the current path between the inside and the outside of the fibre consists only of a resistance and a capacitance in parallel. A good fit of the experimental results on frog fibres is obtained if the inside-outside admittance is considered to contain, in addition to the parallel elements R m = 3100 Ωcm 2 and C m = 2.6 μF/cm 2 , another path composed of a resistance R e = 330 Ωcm 2 in series with a capacitance C e = 4.1 μF/cm 2 , all referred to unit area of fibre surface. The impedance behaviour of crayfish fibres can be described by a similar model, the corresponding values being R m = 680 Ωcm 2 , C m = 3.9 μF/cm 2 , R e = 35 Ωcm 2 , C e = 17 μF/cm 2 . The response of frog fibres to a step-function current (with the points of voltage recording and current application close together) has been analyzed in terms of the above two-time constant model, and it is shown that neglecting the series resistance would have an appreciable effect on the agreement between theory and experiment only at times less than the halftime of rise of the response. The elements R m and C m are presumed to represent properties of the surface membrane of the fibre. R e and C e are thought to arise not at the surface, but to be indicative of a separate current path from the myoplasm through an intracellular system of channels to the exterior. In the case of crayfish fibres, it is possible that R e (when referred to unit volume) would be a measure of the resistivity of the interior of the channels, and C e the capacitance across the walls of the channels. In the case of frog fibres, it is suggested that the elements R e , C e arise from the properties of adjacent membranes of the triads in the sarcoplasmic reticulum . The possibility is considered that the potential difference across the capacitance C e may control the initiation of contraction.

scholarly journals Electrical properties of toad sartorius muscle fibres in summer and winter

1973 ◽  
Vol 230 (3) ◽  
pp. 619-641 ◽  
Author(s):  
Angela F. Dulhunty ◽  
Peter W. Gage
Keyword(s):  
Electrical Properties ◽  
Sartorius Muscle ◽  
Muscle Fibres

Coxal Muscle Receptors in the Crab: The Receptor Potentials of S and T Fibres in Response to Ramp Stretches

1971 ◽  
Vol 55 (3) ◽  
pp. 813-832
Author(s):  
B. M. H. BUSH ◽  
ALAN ROBERTS
Keyword(s):  
Motor Nerve ◽  
Large Diameter ◽  
Muscle Fibres ◽  
Dynamic Component ◽  
Static Responses ◽  
Basal Joint ◽  
Muscle Receptors ◽  
Shore Crabs ◽  
Static Nature ◽  
Receptor Muscle

1. Intracellular and extracellular recordings from the two large-diameter S and T sensory fibres of the posterior thoracico-coxal muscle receptor in shore crabs confirm the graded, dynamic-static nature of the receptor potentials evoked by stretching the receptor muscle, and the lack of afferent impulses. 2. Slow ramp-function stretches evoke receptor potentials with characteristic shapes, which differ between the two fibres in several respects: (i) The dynamic component in the S fibre resembles an algebraic sum of length and velocity responses and a variable initial ‘acceleration’ (?) transient, while in the T fibre it commonly declines (‘adapts’) during stretching, especially at greater velocities and starting lengths. (ii) On release of stretch the S fibre usually exhibits a ‘negative velocity response’, but the T fibre repolarizes rapidly often with a slight hyperpolarization. (iii) The dynamic response of the T fibre is generally greater than that of the S fibre, and increases more steeply and approximately logarithmically with stretch velocity over a 10- to 50-fold range. (iv) The ‘static response’ or degree of depolarization increases fairly linearly with receptor length in the S fibre but very non-linearly in the T fibre. (v) The T fibre displays pronounced hysteresis in its dynamic and static responses at increasing and decreasing lengths, but the S fibre shows little hysteresis. (vi) The T fibre but not the S fibre commonly shows small rapid oscillations or ‘noise’ superimposed upon strongly depolarized ‘static’ potentials. (vii) The S and T responses may be affected reciprocally by some forms of receptor muscle contraction. 3. Graded receptor potentials evoked in the ‘D’ fibre by stretching the non-muscular depressor-receptor strand of the coxo-basal joint show little hysteresis. 4. Receptor muscle fibres respond to motor nerve stimulation or spontaneous motor impulses from the thoracic ganglion with slow, facilitating and summating excitatory junctional potentials. 5. The mechanisms underlying the differences between S and T responses, and their functional significance to the animal, are discussed, and comparisons are drawn with other muscle receptors.

Effects of stimulation and rest on the ultrastructure of the excitatory neuromuscular junctions of Locusta migratoria L.

1979 ◽  
Vol 203 (3) ◽  
Author(s):  
R.P. Botham ◽  
D.J. Beadle ◽  
R.J. Hart ◽  
C. Potter ◽  
R.G. Wilson
Keyword(s):  
Neuromuscular Junctions ◽  
Locusta Migratoria

scholarly journals Acetylcholinesterase from the motor nerve terminal accumulates on the synaptic basal lamina of the myofiber.

1991 ◽  
Vol 115 (3) ◽  
pp. 755-764 ◽  
Author(s):  
L Anglister
Keyword(s):  
Basal Lamina ◽  
Ache Activity ◽  
Neuromuscular Junctions ◽  
Motor Nerve ◽  
Synaptic Cleft ◽  
Motor Nerve Terminal ◽  
Nerve Terminals ◽  
Axon Terminals ◽  
Muscle Nerve ◽  
Almost All

Acetylcholinesterase (AChE) in skeletal muscle is concentrated at neuromuscular junctions, where it is found in the synaptic cleft between muscle and nerve, associated with the synaptic portion of the myofiber basal lamina. This raises the question of whether the synaptic enzyme is produced by muscle, nerve, or both. Studies on denervated and regenerating muscles have shown that myofibers can produce synaptic AChE, and that the motor nerve may play an indirect role, inducing myofibers to produce synaptic AChE. The aim of this study was to determine whether some of the AChE which is known to be made and transported by the motor nerve contributes directly to AChE in the synaptic cleft. Frog muscles were surgically damaged in a way that caused degeneration and permanent removal of all myofibers from their basal lamina sheaths. Concomitantly, AChE activity was irreversibly blocked. Motor axons remained intact, and their terminals persisted at almost all the synaptic sites on the basal lamina in the absence of myofibers. 1 mo after the operation, the innervated sheaths were stained for AChE activity. Despite the absence of myofibers, new AChE appeared in an arborized pattern, characteristic of neuromuscular junctions, and its reaction product was concentrated adjacent to the nerve terminals, obscuring synaptic basal lamina. AChE activity did not appear in the absence of nerve terminals. We concluded therefore, that the newly formed AChE at the synaptic sites had been produced by the persisting axon terminals, indicating that the motor nerve is capable of producing some of the synaptic AChE at neuromuscular junctions. The newly formed AChE remained adherent to basal lamina sheaths after degeneration of the terminals, and was solubilized by collagenase, indicating that the AChE provided by nerve had become incorporated into the basal lamina as at normal neuromuscular junctions.

Sign in / Sign up

Export Citation Format

Share Document