Muscle Receptor Organ Research Articles

The distribution of GABA sensitivity on crayfish muscle receptor organs.

1. The effectiveness of inhibition of gamma-aminobutyric acid (GABA) at various points on crayfish abdominal muscle receptor organs (MROs) was investigated by iontophoretic methods that have a spatial resolution of 8 mum. 2. The MROs in the rostral abdominal segments, which receive inhibitory innervation, were always strongly inhibited by focal iontophoretic application of GABA; MROs in the 6th abdominal segment, which do not receive inhibitory innervation, were usually not strongly inhibited. 3. In the rostral MROs, the magnitude of GABA current necessary to abolish stretch induced impulses was least for dendritic points; it increased as a function of distance from the dendrites, over an area extending from the receptor muscle to a point on the axon 200 mum from the cell body. 4. Outward currrents from NaCl-filled micropipettes had no effect on impulse production when applied to the dendritic region of rostral MROs, but could produce transient inhibition of impulses when applied to the axon. 5. It is suggested that a high degree of GABA sensitivity is localized to the rostral MRO dendrites, where inhibitory synapses are most numerous.

Command fiber control of crayfish abdominal movement

1. The control of abdominal extension and flexion movements in the crayfishOrconectes rusticus, O. virilis andProcambarus clarkii was examined by monitoring the afferent and efferent unit activities in the dorsal nerve of the second abdominal segment during unrestrained abdominal extensions and flexions which were evoked by stimulation of command fibers (CFs) in the circumesophageal connective (CC). 2. CFs which when stimulated generate coordinated extensions and flexions are present in the CC ofP. clarkii. 3. Two classes of extension CFs are present in the CC ofP. clarkii: 1. those which excite the motor neuron (#4) which innervates the tonic receptor muscle (RM1) of the muscle receptor organ; 2. those which excite one or more of the excitatory motorneurons which do not innervate RM1 (#2, #3 and #6). 4. The extensor motorneurons are activated in reciprocal sets by CF stimulation. The inhibitory motor neuron (#5) is silent during CF evoked extensions (inP. clarkii.) 5. During flexion CF stimulation the inhibitory extensor motorneuron is excited while activity in the excitatory extensor motorneurons is suppressed. 6. The strong reciprocity observed in the superficial extensor motor neuron (SEMN) activities evoked by CF stimulation contrasts with the weak reciprocity which is characteristic of extensor motorneuron activities generated by the intact animal which moves its abdomen in response to a strong sensory stimulus (Sokolove, 1973). This difference in reciprocity supports the hypothesis that an intact animal initiates a postural movement of its abdomen by the conjoint excitation of several CFs. 7. Few if any extension CFs are present in the CC ofO. rusticus orO. virilis.

Stretch Receptor Organs in the Thorax of the Hermit Crab,Pagurus Bernhardus(L. 1758)

Muscle receptor organs (MRO) are present in the abdomen in a wide variety of higher Crustacea (see review by Alexandrowicz, 1967), though most experimental work on these organs has been carried out on representatives of only the Astacura and Palinura, in which the anatomy is relatively uniform. In the very varied group Anomura, they have been reported from among the Galatheidea, Thalassinidea and Paguridea (Alexandrowicz 1952b; Pilgrim, 1960); in the latter paper, they were shown to have properties physio-logically similar to those of the Astacura and Palinura, with slowly- and fast-adapting components. Stretch sensitive organs also occur in the thorax of many forms, but are of two distinct types there. In the posterior thorax are MRO comparable with those of the abdomen, i.e. comprising receptor cell, specialized muscle and a complex innervation of excitatory and inhibitory nerves as well as sensory fibres. In the more anterior thorax are the relatively very simple N-cells, whose dendrites spread among the fibres of non-specialized muscle and which are not known to possess any accessory innervation (Alexandrowicz, 1952a).

The Mechanism of the Pupal Gin Trap

ABSTRACT The sensilla inside the gin trap are connected with an intemeurone in the ipsilateral connective above the ganglion in which their axons terminate. This cell is driven by the combined input of many fibres in the afferent bundle; it receives an inhibitory input driven by the contralateral muscle receptor organ and another driven by the contralateral trap sensilla. There is an inhibitory relation between efferent activity on opposite sides of the nervous system. A model is proposed which enhances contrast between the two halves of the nervous system by an inhibitory cross-connexion. The closure mechanism of the gin trap does not fit this model but can be derived from it by a small change in the properties of the ipsilateral junction of triggering sensilla and second-order neurones. A consequence of this theory is that the terminals of the triggering sensilla need not be identified within the central nervous system.

Axial Skeleton and Musculature in the Thorax of the Hermit Crab,Pagurus Bernhardus[Anomura:Paguridae

During an examination of the distribution and relationships of muscle receptor organs in the hermit crab,Pagurus bernhardus(Pilgrim, in preparation), it was found that not enough was known about the muscular anatomy of the animal for the experimental work to be described satisfactorily. This paper is therefore an account of the anatomy appropriate to a better understanding of the receptor organs. In the preparation of this account, it was necessary to examine the skeleton of the animal in great detail, since a knowledge of the relationships of especially the movable skeletal parts is basic for an understanding of the muscular system. The study also forms part of a series in which the comparative anatomy of the axial skeleto-muscular systems is examined in the Decapoda. This paper falls naturally into two parts, dealing respectively with the skeleton and the muscles. Although emphasis in this work is on the trunk anatomy of the last six segments of the thorax, it is necessary to extend observations beyond this region for certain interpretations.

Sensory activity of the mandibular muscle receptor organ ofHomarus gammarus(L)

The mandibular muscle receptor organ (Mand. M.R.O.) of Homarus gammarus (L) exhibits increased activity to receptor muscle (R.M.) contraction (decrease in length) and to stretch (increase in length). The sensory units of this receptor differ in their threshold to R.M. tension and in the frequency change they exhibit for a given increment in tension. The units fire tonically during maintained tension once their threshold has been reached. Both the number of active units and their frequency increase with R.M. tension. The Mand. M.R.O. is velocity sensitive and exhibits a higher degree of activity during rapid stretch. This dynamic response increases with rate of R.M. stretch. The activity of the Mand. M.R.O. sensory neurones is compared with that of other M.R.O.’s and the authenticity of some aberrant units is discussed.

Crayfish muscle receptor organ: role in regulation of postural flexion.

Recordings were made from postural-control motor nerves with antagonistic functions in the crayfish abdomen through flexible suction electrodes. During unrestrained flexion of the abdomen, output from the tonic stretch receptor neuron of RM(1),(SR(1)) is sufficient to drive an extensor motor unit in the same segment. However, this intrasegmental "resistance" reflex is normally blocked by an intersegmental reflex in which output from SR(1)'s in caudal segments inhibits SR(1) discharge in more anterior segments.

A muscle receptor organ in the scorpion postabdomen

A muscle receptor organ in the scorpion postabdomen

A muscle receptor organ in the scorpion postabdomen

1. Information on the relative orientation of each of the muscles in scorpion postabdominal segment 3 is presented (Fig. 1). All main muscles insert on the posterior segment and are operational at the posterior joint. The receptor muscle, which lies in parallel with the extensor muscle, is stretched by posterior joint flexion, and released by extension. 2. Unilateral MRO stretch and release elicits bilateral reflex output to each of the muscles (Figs. 3, 4). Increased Aff. 2 input excites the motoneuron populations of the extensor, ventral lateral, dorsal lateral muscles and inhibits tonic flexor motoneuron discharge. MRO stretch reflexly excites the receptor muscle (Fig. 4). 3. Sensory and reflex data are combined to formulate a model of the role played by the scorpion MROs in postabdominal position control (Fig. 6). It appears that the receptor system is particularly well suited to stabilize postabdominal geometry in the dorso-ventral plane by independently resisting imposed flexion at each joint level.

The mandibular muscle receptor organ of Homarus gammarus (L.) (crustacea, decapoda)

A muscle receptor organ is present in the mandible of macruran decapods. The mandibular muscle receptor organ (Mand. MRO) of Homarus gammarus (L.) consists of a ribbon of muscle innervated at its ventral insertion by 10–20 multiterminal sensory neurones. The sensory cells have a small number of dendritic processes.

Phonoreception in some Coleoptera infesting stored products

Mechanoreceptors that could be phonoreceptive were located and studied in Sitophilus oryzae (L.), with preliminary tests also on Sitophilus granarius (L.). Tribolium confusum (Herbst), Attagenus piceus (Olivier), and Trogoderma inclusum LeC. Various behavioral responses of tethered (mounted) beetles were used as indices of reception of air-borne and solid-borne sounds of known frequencies and pound pressure levels. The probable receptors for air-borne sounds in S. oryzae are the well developed Johnston's organs in the second antennal segments, and tactile hairs on the bodies. Both are primarily sensitive to air movements or contact, and sounds are active only at relatively high intensities or in the near-field. The probable receptors for solid-borne sounds (vibrations) are chordotonal organs of the legs, which have relatively high sensitivity, and possibly the muscle receptor organs of the body wall. These four potential phonoreceptors are described and figured. The low sensitivity to air-borne sounds and high sensitivity to solid-borne sounds is probably related to the specialized habits of these insects.

Thermoelastic tension changes in the muscles of the abdominal stretch receptors of the crayfish

1. 1. Under isometric conditions the receptor muscles of the abdominal stretch receptor of Astacus leptodactylus show an anomalous thermoelastic behaviour. 2. 2. Thermoelastic changes in tension increase in proportion with rising preliminary stress and greater parallel-elastic forces. 3. 3. The temporary rise in frequency of the receptor discharge at the beginning of the cooling period is not reflected in the constant fall in muscle tension. 4. 4. The same rate of discharge can be obtained by means of considerably smaller tension changes in the case of thermoelastic than in the case of mechanical strain. 5. 5. As a result of items 2 and 3 the causes for frequency changes after temperature jumps must be sought in temperature-dependent membrane processes in addition to thermoelastic tension changes of the muscle receptor organ (MRO).

Observations on receptor mechanisms in Ligia oceanica (Linn.)

1. 1. Activity probably derived from a dorsal muscle receptor organ has been detected in the dorsal branch of the fourth intersegmental thoracic nerve. 2. 2. The uropods have mechanoreceptors associated with them, the inner one responding only to depression and the outer to elevation. There is also a vibration receptor associated with the inner ramus. 3. 3. A number of sensory spines on the ventral surfaces of the pereiopods have been investigated.

Screening for neurotransmitters: a rapid radiochemical procedure.

AbstractAmong the known or suspected neurotransmitter compounds are: acetylcholine, norepinephrine, γ‐aminobutyric acid, epinephrine, 5‐hydroxytryptamine, dopamine, and octopamine. This communication describes a rapid screening procedure for identifying which of these substances are likely candidates for neurotransmitters in a particular tissue. The method is based on the selective synthesis and localization of transmitters in those cells which are presumed to release them. The procedural steps are: (1) incubation of tissue in a physiological medium containing one or more radiochemical precursors of suspected transmitters; (2) acidic extraction of all or selected parts (e.g., single cells) of the incubated tissue; (3) high‐voltage paper electrophoresis of the extract under conditions which separate most of the compounds of interest; and (4) quantification of isotope in each transmitter candidate. The effectiveness and sensitivity of the method have been shown with several preparations whose transmitters are known. In certain cases the sensitivity can extend to a single cell level. Preliminary results are also reported on the application of the technique to a lobster sensory system of unknown transmitter chemistry, the abdominal muscle receptor organ.

Fine structural localization of acetylcholinesterase in sensory and motor neurons of the muscle receptor organ in homarus.

AbstractHistochemical techniques with the electron microscope for the localization of specific acetylcholinesterase and non‐specific cholinesterases have been applied to preparations of the abdominal muscle receptor organ, or stretch receptor, of the lobster. Reaction product specific for AChE was found to be localized in a discrete but interrupted fashion on the external surface of the cell membranes of both the fast and slow sensory neurons at the levels of axon, cell body, large and small dendritic processes, and fine dendritic terminations. Reaction product specific for AChE was also found on the external surface of the limiting membranes of motor axons, but not at neuromuscular endings. Non‐specific ChE was limited to cytoplasmic vacuoles and cisternae of the Schwann cells of the neural sheaths. These findings lend support to the hypothesis that in the lobster the ACh system may mediate membrane excitability of nerve fibers. Furthermore, at the level of dendritic terminations this system may mediate the transduction of mechanical into electrical energy via reversible permeability changes.

Length and tension hysteresis during sinusoidal and step function stimulation of arthropod muscle.

ARTICLESLength and tension hysteresis during sinusoidal and step function stimulation of arthropod muscleDM Wilson, DO Smith, and P DempsterDM Wilson, DO Smith, and P DempsterPublished Online:01 Mar 1970https://doi.org/10.1152/ajplegacy.1970.218.3.916MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByForce–length relation of skeletal muscles: from sarcomeres to myofibril26 July 2018 | Biomechanics and Modeling in Mechanobiology, Vol. 17, No. 6Hysteresis in the production of force by larval Dipteran muscleJournal of Experimental Biology, Vol. 213, No. 14Invertebrate muscles: Thin and thick filament structure; molecular basis of contraction and its regulation, catch and asynchronous muscleProgress in Neurobiology, Vol. 86, No. 2Non-uniformity of sarcomere lengths can explain the ?catch-like? effect of arthropod muscleJournal of Muscle Research and Cell Motility, Vol. 15, No. 5Active supercontraction in rolling-up muscles ofGlomeris marginata (myriapoda, diplopoda)Journal of Morphology, Vol. 172, No. 1MuscleMuscle, the Motor1 January 2011Motor Units: Anatomy, Physiology, and Functional Organization1 January 2011Reflexes mediated by non-impulsive afferent neurones of thoracic-coxal muscle receptor organs in the crab,Carcinus maenasJournal of Comparative Physiology ? A, Vol. 142, No. 1On the function of the common inhibitory neurone in the walking legs of the crab,Eriphia spinifronsJournal of Comparative Physiology ? A, Vol. 143, No. 1Maintained contraction of the crayfish claw opener muscle in the absence of motor neuron activityBrain Research, Vol. 162, No. 1Organization of Invertebrate Motor Systems1 January 2011A Review of Apparatus for Investigating the Mechanical Properties of Soft Animal Tissue in Vitro1 December 2016 | Engineering in Medicine, Vol. 6, No. 4A paradigm for position learning in the crayfish clawBrain Research, Vol. 134, No. 1An in vitro study of prolonged vasospasm of a rabbit cerebral artery.Stroke, Vol. 7, No. 2Temporal characteristics of efferent neuron discharge during muscle contraction in the crayfish clawJournal of Comparative Physiology ? A, Vol. 96, No. 4ARTHROPOD MUSCLE More from this issue > Volume 218Issue 3March 1970Pages 916-922 Copyright & PermissionsCopyright © 1970 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1970.218.3.916PubMed5414053History Published online 1 March 1970 Published in print 1 March 1970 Metrics

Observations on the organization of the dendritic processes and receptor terminations in the abdominal muscle receptor organ of Homarus.

AbstractThe dendritic processes and terminals of the abdominal muscle receptor organ of the lobster have been studied with the electron microscope. In both the “fast” and “slow” adapting components of the muscle receptor organ, dendritic processes ramify within the body of the stretch muscle in a zone of “relative muscle exclusion,” where the continuity of the muscle bundle is interrupted by a zone of connective tissue. The cell bodies and larger dendritic processes are ensheathed in alternate layers of connective tissue and Schwann cells, but the smallest dendritic twigs are entirely divested of their Schwann cell envelope. The membrane of the dendritic terminations is intimately applied to either connective tissue of the zone of relative muscle exclusion or to the sarcolemma of the stretch muscle. This apposition is interpreted as morphological specialization for transduction or mechanoelectric conversion. It is suggested that these two types of dendritic terminals may represent two distinct sites for transduction and may also mediate different modalities of input.The distribution of dendritic processes and terminals differs in the fast and slow systems. In the fast system the dendrites quickly ramify into a glomerular burst of processes near the junction of stretch muscle and connective tissue. In the slow system, the dendrites ramify more gradually and lie more nearly parallel to the long axis of the stretch muscle.In both the fast and slow systems, but especially in the dendritic terminals of the fast neuron, collections of vesicles 400–2000 Å in diameter have been observed. These vesicles are clearly different in fine structure from those found in the neuromuscular junction or axo‐dendritic synapses.An effort is made to relate neurophysiological characteristics of this system with the fine structural observations, with particular attention to the mechanism of transduction, or mechanoelectric conversion.

Proprioceptive control of posture in the crayfish abdomen.

ABSTRACT Sense organs responsive to the changes produced by an animal’s own musculature are common in complex, flexible motor systems, and it is probably safe to assume that proprioceptive feedback is required for these systems to operate with precision. The crustacean muscle receptor organ (MRO) first described by Alexandrowicz (1951) has, because of its accessibility, ease of isolation and hardiness, proven particularly amenable to electrophysiological study. However, the study of this receptor has until recently been confined to mechanisms of transduction and to the excitatory and inhibitory control of its output.

Sensory modalities and receptive fields in the abdominal nervous system of the hermit crab, Pagurus granosimanus (Stimpson).

ABSTRACT The way in which adaptation to a particular environment takes place within the central nervous system of vertebrates has been the subject of research for over a hundred years. The development of specific reflexes from generalized action patterns, the precedence of changes in motor systems over changes in sensory systems, and the metamorphosis of sensory relay nuclei and centres of primary integration into areas subserving more complex functions (Herrick, 1948) are some of the ways in which adaptation is reported to have occurred. Furthermore, Bishop (1961) has suggested that the emphasis upon functional criteria alone as a key to the function of a specific nervous system neglects those features of the system which owe their presence to its evolution from a nervous system adapted to perform other tasks. During their evolution, the newer centres of integration which have developed as a result of new requirements have not abolished the older centres, which may retain many of their old properties. It is clearly of interest to determine whether nervous systems of groups other than vertebrates exhibit the same regularities in their adaptation, and if possible to examine the alterations in response to different selective forces at the single-unit level.

Functional role of muscle receptor organs in crayfish.

Functional role of muscle receptor organs in crayfish.