An Arthropod Muscle Innervated by Nine Excitatory Motor Neurones

The anatomical and physiological organization of the locust metathoracic flexor tibiae was examined by a combination of intracellular recording and electron microscopy. Nine excitatory motor neurones, three fast, three intermediate and three slow innervate the muscle; each is uniquely identifiable using a combination of physiological response and soma location. A simple spatial distribution of inputs to the muscle from the individual motor neurones was not found. Individual muscle fibres responded to as many as seven of the motor neurones in various combinations. The muscle fibres are heterogeneous, ranging from slow (tonic) to fast (phasic) in a continuum from predominantly phasic proximally to tonicdistally. This is demonstrated by contraction and relaxation rates to directand indirect stimulation, as well as contraction elicited by action potentials in a single flexor motor neurone. The fast and slow contractile properties of the muscle fibres are matched by appropriate ultrastructures. Such a high degree of complexity of neuromuscular innervation as that found in the metathoracic flexor tibiae has not previously been described for an arthropod muscle.

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Central connections of sensory neurones from a hair plate proprioceptor in the thoraco-coxal joint of the locust.

Journal of Experimental Biology ◽

10.1242/jeb.198.7.1589 ◽

1995 ◽

Vol 198 (7) ◽

pp. 1589-1601 ◽

Cited By ~ 1

Author(s):

F Kuenzi ◽

M Burrows

Keyword(s):

Stance Phase ◽

Swing Phase ◽

Motor Neurone ◽

Sensory Neurone ◽

Sensory Neurones ◽

Selective Stimulation ◽

Basal Joint ◽

Motor Neurones ◽

Individual Motor ◽

Stimulation Of

The hair plate proprioceptors at the thoraco-coxal joint of insect limbs provide information about the movements of the most basal joint of the legs. The ventral coxal hair plate of a middle leg consists of group of 10-15 long hairs (70 microns) and 20-30 short hairs (30 microns). The long hairs are deflected by the trochantin as the leg is swung forward during the swing phase of walking, and their sensory neurones respond phasically during an imposed deflection and tonically if the deflection is maintained. Selective stimulation of the long hairs elicits a resistance reflex that rotates the coxa posteriorly and is similar to that occurring at the transition from the swing to the stance phase of walking. The motor neurones innervating the posterior rotator and adductor coxae muscles are excited, and those to the antagonistic anterior rotator muscle are inhibited. By contrast, selective stimulation of the short hairs leads only to a weak inhibition of the anterior rotator. The excitatory effects of the long hairs are mediated, in part, by direct connections between their sensory neurones and particular motor neurones. A spike in a sensory neurone elicits a short-latency depolarising postsynaptic potential (PSP) in posterior rotator and adductor motor neurones whose amplitude is enhanced by hyperpolarising current injected into the motor neurone. When the calcium in the saline is replaced with magnesium, the amplitude of the PSP is reduced gradually, and not abruptly as would be expected if an interneurone were interposed in the pathway. Several sensory neurones from long hairs converge to excite an individual motor neurone, evoking spikes in some motor neurones. The projections of the sensory neurones overlap with some of the branches of the motor neurones in the lateral association centre of the neuropile. It is suggested that these pathways would limit the extent of the swing phase of walking and contribute to the switch to the stance phase in a negative feedback loop that relieves the excitation of the hairs by rotating the coxa backwards.

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An elaborate tension receptor system highlights sensory complexity in the hind leg of the locust

Journal of Experimental Biology ◽

10.1242/jeb.198.8.1673 ◽

1995 ◽

Vol 198 (8) ◽

pp. 1673-1689 ◽

Cited By ~ 5

Author(s):

T Matheson ◽

L Field

Keyword(s):

Muscle Tension ◽

Muscle Length ◽

Motor Units ◽

Motor Neurone ◽

Muscle Fibres ◽

Sense Organs ◽

Flexor Muscle ◽

Receptor System ◽

Motor Neurones ◽

Antagonistic Muscles

The tibia of each leg of the locust is moved by two antagonistic muscles, the extensor and flexor tibiae. A variety of sense organs on and in each leg provide feedback about this joint's position and movement and about forces acting on the exoskeleton and muscles. One such organ is a muscle tension receptor found within the flexor tibiae muscle of the mesothoracic leg. We now show that an apparently homologous multipolar receptor is present in the hind leg, but that here it is associated with a specialised flexor muscle, the accessory flexor. This muscle comprises 13 fibres, innervated by five of the thirteen motor neurones that innervate the main flexor muscle and, since these are slow motor units, the response properties of the receptor are constrained. The multipolar receptor attaches to the muscle fibres near their proximal insertion onto the femoral cuticle. It generally has four primary dendrites, which do not branch extensively within the muscle. We show that the receptor responds strongly to active, isometric contractions but only poorly to imposed changes of accessory flexor muscle length (i.e. passive changes in tibial position). It does not respond to tension generated by the main flexor muscle or by the extensor muscle. The tension receptor causes short-latency (0.91.8 ms) excitatory inputs onto the three common inhibitory motor neurones and longer-latency (3.78.1 ms) inhibitory inputs onto the slow extensor tibiae motor neurone. In quiescent animals, it causes excitatory inputs onto flexor tibiae motor neurones (2.23.8 ms) but, in more active animals, its inputs onto these neurones are often inhibitory, with delays of 610 ms. The slow nature of the accessory flexor muscle and the pattern of central connections of the receptor suggest that together they are involved in the control of slow movements or posture, potentially acting through a servomechanism.

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Numbers and contraction-values of individual motor-units examined in some muscles of the limb

Proceedings of the Royal Society of London. Series B, Containing Papers of a Biological Character ◽

10.1098/rspb.1930.0032 ◽

1930 ◽

Vol 106 (745) ◽

pp. 326-357 ◽

Cited By ~ 224

Keyword(s):

Motor Unit ◽

Motor Nerve ◽

Motor Units ◽

Muscle Fibres ◽

Total Potential ◽

Quantitative Statement ◽

Effector Organ ◽

Quantum Reaction ◽

The Individual ◽

Individual Motor

“The muscle with its nerve may be thought of as an additive assemblage of motor-units, meaning by motor-unit an individual motor nerve-fibre with the bunch” [or “squad” (E. L. Porter, 1929 (1))]“ of muscle-fibres it activates.” (2) The components of such a unit can claim sufficiently close and sufficiently analysed interrelation to warrant acceptance for many purposes as a single functional entity. In application to reflexes, the unit thus resulting favours brevity and directness of quantitative statement. Its correspondence with a so-to-say quantum reaction, which forms the basis, by combinations temporal and numerical, of all grading of the muscle as effector-organ, fits it for measuring that grading. It is, moreover, applicable centrally as well as peripherally, since the motor-units active number the motoneurones discharging. Such mensuration, the total of the pool of motoneurones being known, evaluates per se the given reaction in terms of the total potential reaction. 1. Contraction-Tension of the Individual Motor-Unit. In the following experiments it was therefore sought to find the physiological size of the motor-unit, i. e. , to measure its contraction-tension. The muscles examined (cat) have been gastrocnemius (median head) soleus, semitendinosus, extensor longus digitorum , and, less fully, tibialis anticus and crureus.

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Peptidergic and Aminergic Modulation of Insect Skeletal Muscle

Journal of Experimental Biology ◽

10.1242/jeb.124.1.143 ◽

1986 ◽

Vol 124 (1) ◽

pp. 143-176 ◽

Cited By ~ 2

Author(s):

PETER D. EVANS ◽

CAMILLA M. MYERS

Keyword(s):

Biogenic Amines ◽

Neuromuscular Transmission ◽

Muscular Contraction ◽

Model Systems ◽

Muscle Fibres ◽

Adenosine Analogues ◽

Modes Of Action ◽

Motor Neurones ◽

Insect Skeletal Muscle ◽

Contraction And Relaxation

Insect skeletal muscles are frequently innervated by small numbers of motor neurones, all of which can be uniquely identified physiologically. They therefore present excellent model systems in which to study the basic principles of neuromuscular transmission and the modulation of these effects by biogenic amines and peptides. The extensor-tibiae muscle of the hind leg of the locust is a much studied, large muscle that is innervated by three identified motor neurones and one identified modulatory neurone. Much attention has recently been focused on the modulation of neuromuscular transmission and muscular contraction in this muscle by biogenic amines and peptides. One proximal bundle of muscle fibres in the extensor-tibiae muscle exhibits a myogenic rhythm of contraction and relaxation. The rhythm is stimulated by a variety of peptides including proctolin, the AKH-related peptides M1 and M2, and by small cardioactive peptide (SCPB). In addition, it is activated by 5-hydroxytryptamine and by oneclass of adenosine analogues. The rhythm is inhibited by octopamine and by a second class of adenosine analogues. The actions of these various modulatory compounds will be discussed in terms of the likely numbers of pharmacologically distinct receptors in this preparation and their modes of action. Neuromuscular transmission and muscular contraction in the extensor-tibiae muscle is modulated by the biogenic amine octopamine and by the peptides, proctolin and FMRFamide. The actions of these modulators are discussed in relation differences in the responsiveness of various regions of the muscle, to the frequency dependence of their effects on motor neurone activityand to their modes of action. The cellular locations and mode of transmission to the muscle of some of these modulators will be considered. Octopamine and proctolin are contained within neurones which innervate the muscle, whilst FMRFamide- and SCPB-like peptides appear to be released into the locust haemolymph as neurohormones.

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The motor innervation of the oviducts and central generation of the oviductal contractions in two orthopteran species (Calliptamus sp. and Decticus albifrons)

Journal of Experimental Biology ◽

10.1242/jeb.198.2.507 ◽

1995 ◽

Vol 198 (2) ◽

pp. 507-520 ◽

Cited By ~ 1

Author(s):

E Kalogianni ◽

G Theophilidis

Keyword(s):

Motor Function ◽

Action Potentials ◽

Motor Pattern ◽

Pattern Generator ◽

Abdominal Ganglion ◽

Muscle Fibres ◽

Descending Inhibition ◽

Metathoracic Ganglion ◽

Motor Neurones ◽

Orthopteran Species

The oviducts of the female Decticus albifrons (Orthoptera: Tettigonidae) are innervated by six bilaterally paired neurones, while those of the female Calliptamus sp. (Orthoptera: Catantopidae) are innervated by three bilaterally paired neurones, located in the seventh abdominal ganglion. Using intracellular recording and staining, five of the six oviductal neurones of D. albifrons and the three oviductal neurones of Calliptamus sp. were physiologically and morphologically identified. All three oviductal neurones of Calliptamus sp. have a motor function. In D. albifrons, however, there is evidence for motor function in only three of the five identified oviductal neurones that appear to participate in the generation of the oviductal contractions. The remaining two identified neurones of D. albifrons have a branching pattern similar to that of motor neurones, but their physiological characteristics, large overshooting soma action potentials (3040 mV) with a long afterhyperpolarising phase, are similar to those of the oviductal unpaired median neurones, which are known to modulate the oviductal contractions. The oviductal muscle exhibits two different modes of contractions: (a) fast and slow myogenic contractions, the fast contractions being produced by spontaneous potentials (3040 mV) generated by some oviductal muscle fibres; and (b) neurogenic contractions caused by the rhythmic spiking of the oviductal motor neurones. This motor pattern is produced by the oviductal central pattern generator, a neural network residing in the last two abdominal ganglia (seventh and terminal abdominal ganglia) of the species examined here. When isolated both anteriorly and posteriorly, the seventh abdominal ganglion generates rhythmic oviductal contractions of lower frequency and amplitude than those recorded when the connectives between the genital ganglia are intact. The oviductal pattern generator is activated through release from descending inhibition, which originates, in Calliptamus sp., from the compound metathoracic ganglion (fused metathoracic and first three abdominal neuromeres) and in, D. albifrons, from the first free abdominal ganglion (fused second and third abdominal neuromeres).

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Neuronal Mechanisms Underlying Crayfish Steering Behaviour as an Equilibrium Response

Journal of Experimental Biology ◽

10.1242/jeb.114.1.599 ◽

1985 ◽

Vol 114 (1) ◽

pp. 599-617

Author(s):

M. Takahata ◽

M. Yoshino ◽

M. Hisada

Keyword(s):

Muscle Activity ◽

Motor Neurone ◽

Inhibitory Input ◽

Equilibrium Response ◽

Neuronal Mechanisms ◽

Terminal Ganglion ◽

Motor Neurones ◽

Body Rolling ◽

Individual Motor

1. When the crayfish Procambarus is rolled with legs not upon a substratum, uropod opener muscles on the lifted side are activated in co-contraction whereas antagonistic closer muscles on the same side are all relaxed simultaneously. The closers are activated and the openers are relaxed on the lowered side. 2. This reciprocal pattern is also observed in the motor neurone activity: the contraction of opener muscles on the lifted side and closer muscles on the lowered side is caused by an increase in the activity of excitatory motor neurones innervating these muscles, whereas the relaxation of their antagonists on each side is caused by a decrease in the activity of excitatory motor neurones innervating them. Deafferentation by cutting all roots of the terminal ganglion has no significant effect on the steering pattern. 3. The decrease in the excitatory motor neurone activity during steering was found to be due to an increase in the inhibitory input to the motor neurones. 4. During body rolling, the statocyst receptors on the lifted side increase their activity while those on the lowered side decrease it (Takahata & Hisada, 1979). We conclude that the opener motor neurones receive excitation and inhibition respectively from the ipsilateral and the contralateral statocyst, whereas the closer motor neurones receive excitation and inhibition respectively from the contralateral and ipsilateral statocyst. From these results, the connections between the motor neurones and the identified statocyst interneurones were deduced. 5. The normal, bilaterally organized steering pattern of the uropod muscle activity seems to be produced by the statocysts of both sides, whose information is mediated by a bilateral set of interneurones having different connections to individual motor neurones.

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The Modulatory Actions of FMRFamide and Related Peptides on Locust Skeletal Muscle

Journal of Experimental Biology ◽

10.1242/jeb.126.1.403 ◽

1986 ◽

Vol 126 (1) ◽

pp. 403-422 ◽

Cited By ~ 1

Author(s):

PETER D. EVANS ◽

CAMILLA M. MYERS

Keyword(s):

Slow Muscle ◽

Motor Neurone ◽

Muscle Fibres ◽

Relaxation Rates ◽

Receptor System ◽

Low Frequencies ◽

Slow Muscle Fibres ◽

Slow Twitch ◽

Frequency Of Stimulation ◽

Stimulation Of

1. The modulatory actions of FMRFamide and related peptides on tension generated in the extensor-tibiae muscle of the locust hindleg by stimulation of the slow excitatory motor neurone (SETi) depend upon the frequency of stimulation of SETi. They have no effect on the tension induced by the fast motor neurone (FETi) or upon the myogenic rhythm present in this muscle. 2. At low frequencies of SETi stimulation (1Hz and below) the predominant modulatory effects are increases in the amplitude, contraction rates and relaxation rates of twitch tension. At higher frequencies, where twitches summate but tetanus is incomplete (up to 20 Hz) these effects are superimposed upon an increase of maintained tension. 3. FMRFamide increases the amplitude and relaxation rate of slow twitch tension by different amounts in different regions of the extensor muscle. It is likely that the effects of FMRFamide are restricted to slow muscle fibres that are innervated by SETi but not FETi. 4. The modulatory actions of FMRFamide on SETi-induced tension are additive to, but do not potentiate, the modulatory actions of octopamine and proctolin in this muscle. The actions of FMRFamide show some similarities with the modulatory actions of octopamine in this preparation but they are mediated by an independent receptor system that does not change cyclic nucleotide levels. Other actions of FMRFamide are similar to the actions of proctolin.

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Semiology of the Pain Syndrome - Identifying the Ideal Methods of Locoregional Anesthesia Based on Their Rationale and Features

Revista de Chimie ◽

10.37358/rc.17.10.5888 ◽

2017 ◽

Vol 68 (10) ◽

pp. 2373-2377

Author(s):

Mihaela Monica Scutariu ◽

Vlad Danila ◽

Corina Ciupilan ◽

Oana Elena Ciurcanu

Keyword(s):

Maxillofacial Surgery ◽

Essential Element ◽

Pain Syndrome ◽

Oral And Maxillofacial Surgery ◽

Structuring Element ◽

Technical Accuracy ◽

Locoregional Anesthesia ◽

Special Approach ◽

The Individual ◽

High Degree

Anesthesia and the degree of control over the perception of pain depends on the personality of the individual, the socio-economic conditions, potential previous painful experiences and, last but not least, on fatigue and fear of the dentist. The perception of pain in patients is closely connected to their mental state. Pain is defined as a sensation of discomfort, with wide variations, both in quality and intensity, for different people in seemingly identical conditions; an unpleasant sensitive and emotional phenomena connected to the threat of a wound or caused in the tissues or described in the terms of this disease. The essential element of any type of anesthesia is analgesia, an effect which in some cases cannot be achived, due to the patient�s particularities or the physician�s lack of experience in anesthesia. Locoregional anesthesia (LRA) represents the blocking of the nociceptive sensitive and sympathetic autonomic afferents as well as that of motor efferents at the level of peripheral nerves� axons, by means of local anesthetic. To achieve the set purpose, we carried out a study on a representative human sample comprised of 10.123 patients treated in the Oral and Maxillofacial Surgery Clinic (Ambulatory) from the County Clinic Emergency Hospital St. Spiridon Iasi, between 01.01.2015-31.12.2016. The reason for the exclusion of certain categories of patients in the reseach was: the patients with a special conditions background require individual pre-anesthesia schemes, personalised for the nature of the pre-existing general condition, which must be further approved by the attending specialist physician : cardiologist, internist, diabetologist; children under 18 years old, with a high degree of anxiety; a high precentage of elderly patients, over 60 years old, possess a combination of general issues, thus requiring a special approach. The thoroughness lying at the core of the anesthetic practice, most especially the safegurading of a technical accuracy in the performance of anesthesia [12,], instead of improvisations, the lack of anatomical and stomatological training in general and the resulting inefficiency as such, is the underlying in-depth structuring element of this paper.

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Territories of state-led aquaculture risk management: Thailand’s Plang Yai program

Environment and Planning C Politics and Space ◽

10.1177/2399654420965241 ◽

2020 ◽

pp. 239965442096524

Author(s):

Mariska JM Bottema ◽

Simon R Bush ◽

Peter Oosterveer

Keyword(s):

Risk Management ◽

Policy Instruments ◽

Spatially Explicit ◽

Financial Risks ◽

Shared Resources ◽

Globalizing World ◽

Farmer Behavior ◽

Key Policy ◽

The Individual ◽

High Degree

The Thai aquaculture sector faces a range of production, market and financial risks that extend beyond the private space of farms to include public spaces and shared resources. The Thai state has attempted to manage these shared risks through its Plang Yai (or ‘Big Area’) agricultural extension program. Using the lens of territorialization, this paper investigates how, through the Plang Yai program, risk management is institutionalized through spatially explicit forms of collaboration amongst farmers and between farmers and (non-)state actors. We focus on how four key policy instruments brought together under Plang Yai delimited multiple territories of risk management over shrimp and tilapia production in Chantaburi and Chonburi provinces. Our findings demonstrate how these policy instruments address risks through dissimilar but overlapping territories that are selectively biased toward facilitating the individual management of production risks, whilst enabling both the individual and collective management of market and financial risks. This raises questions about the suitability of addressing aquaculture risks by controlling farmer behavior through state-led designation of singular, spatially explicit areas. The findings also indicate the multiple roles of the state in territorializing risk management, providing a high degree of flexibility, which is especially valuable in landscapes shared by many users, connected to (global) value chains and facing diverse risks. In doing so we demonstrate that understanding the territorialization of production landscapes in a globalizing world requires a dynamic approach recognizing the multiplicity of territories that emerge in risk management processes.

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