scholarly journals The Organization and Role During Locomotion of the Proximal Musculature of the Cricket Foreleg: I. Anatomy and Innervation

1986 ◽  
Vol 123 (1) ◽  
pp. 255-283
Author(s):  
GILLES LAURENT ◽  
DANIEL RICHARD

Reprint requests should be sent to D. Richard at this address. The structure of the proximal segments of the cricket (Gryllus bimaculatus) foreleg, together with the associated musculature and its innervation are described. The morphology of 50 motor neurones involved in the control of this musculature has been revealed using backfilling techniques with cobalt, horseradish peroxidase and Lucifer Yellow. The ‘ball and socket’ pleurocoxal joint is moved by three sets of anatomical antagonists (promotor-remotor, abductor-adductor, anterior-posterior rotator muscles) inserted on each side of the three axes of rotation. The axial coxotrochanteral joint is moved by the intrinsic levator and the depressor muscles; these depressors are composed of an intrinsic (coxotrochanteral) and a ‘double’ (pleurotrochanteral) subgroup. The double depressors, and all the muscles inserting on the trochantin (promotors) or the anterior coxal rim (adductor, abductors, anterior rotators) are supplied by at least eighteen neurones, whose axons run in nerve 3. The muscles that insert on the posterior coxal rim (remotors, posterior rotators) are innervated by at least twelve similar neurones whose axons run in nerve 4. The intrinsic coxal muscles are supplied by branches of nerve 5 (ten motor neurones to the levators, two to the depressors). Three presumably common inhibitors, and one Dorsal Unpaired Median (DUM) neurone have also been found.

1985 ◽  
Vol 100 (3) ◽  
pp. 851-859 ◽  
Author(s):  
J A Swanson ◽  
B D Yirinec ◽  
S C Silverstein

Lucifer Yellow CH (LY) is an excellent probe for fluid-phase pinocytosis. It accumulates within the macrophage vacuolar system, is not degraded, and is not toxic at concentrations of 6.0 mg/ml. Its uptake is inhibited at 0 degree C. Thioglycollate-elicited mouse peritoneal macrophages were found to exhibit curvilinear uptake kinetics of LY. Upon addition of LY to the medium, there was a brief period of very rapid cellular accumulation of the dye (1,400 ng of LY/mg protein per h at 1 mg/ml LY). This rate of accumulation most closely approximates the rate of fluid influx by pinocytosis. Within 60 min, the rate of LY accumulation slowed to a steady-state rate of 250 ng/mg protein per h which then continued for up to 18 h. Pulse-chase experiments revealed that the reduced rate of accumulation under steady-state conditions was due to efflux of LY. Only 20% of LY taken into the cells was retained; the remainder was released back into the medium. Efflux has two components, rapid and slow; each can be characterized kinetically as a first-order reaction. The kinetics are similar to those described by Besterman et al. (Besterman, J. M., J. A. Airhart, R. C. Woodworth, and R. B. Low, 1981, J. Cell Biol. 91:716-727) who interpret fluid-phase pinocytosis as involving at least two compartments, one small, rapidly turning over compartment and another apparently larger one which fills and empties slowly. To search for processes that control intracellular fluid traffic, we studied pinocytosis after treatment of macrophages with horseradish peroxidase (HRP) or with the tumor promoter phorbol myristate acetate (PMA). HRP, often used as a marker for fluid-phase pinocytosis, was observed to stimulate the rate of LY accumulation in macrophages. PMA caused an immediate four- to sevenfold increase in the rate of LY accumulation. Both HRP and PMA increased LY accumulation by stimulating influx and reducing the percentage of internalized fluid that is rapidly recycled. A greater proportion of endocytosed fluid passes into the slowly emptying compartment (presumed lysosomes). These experiments demonstrate that because of the considerable efflux by cells, measurement of marker accumulation inaccurately estimates the rate of fluid pinocytosis. Moreover, pinocytic flow of water and solutes through cytoplasm is subject to regulation at points beyond the formation of pinosomes.


1993 ◽  
Vol 174 (1) ◽  
pp. 123-138 ◽  
Author(s):  
E. Kalogianni ◽  
G. Theophilidis

The rhythmic firing pattern of the putatively octopaminergic dorsal unpaired median (DUM) neurones supplying the oviductal system of female orthopterans, Calliptamus sp. and Decticus albifrons, was examined. Our data provide evidence that the oviductal DUM neurones in the seventh abdominal ganglion modulate the oviductal motor pattern, both peripherally and centrally, during the inhibition of egg-laying behaviour. In a minimally dissected animal, rhythmic activation of the oviductal DUM and motor neurones can be readily elicited by isolation of the seventh abdominal ganglion from the anterior part of the nerve cord. The bursting activity of the DUM neurones is temporally correlated with the oviductal motor rhythm. Both populations of oviductal neurones retain their rhythmic firing pattern after total isolation of the genital ganglia, indicating the presence of an oviductal central pattern generator. The effects of stimulation of oviductal DUM neurones on the oviductal motor activity were monitored by recording intracellularly from oviductal muscle fibres and extracellularly from motor axons. These effects consist of a reduction in the amplitude and frequency of excitatory postsynaptic potentials (EPSPs) in the muscle fibre and in the firing rate in oviductal motor neurones. We suggest that the change in EPSP amplitude results from peripheral release of octopamine by DUM neurones. The decreased firing rate of motor neurones, however, appears to be a central effect, possibly caused by central release of octopamine by DUM neurones.


Three types of sensory neurones and two kinds of motor neurones in the segmental ganglion of the leech were examined with the light and electron microscope after intracellular injection of horseradish peroxidase (HRP) for a histological marker. The aim was to develop a method for identifying the synapses of specific cells in the ganglion’s complex neuropil and to form a picture of their distribution and structure. Reaction of HRP with different benzidine derivatives produces opaque and electron dense deposits. For light microscopy a blue stain is formed that makes processes visible in whole mounts millimeters away from the injection site at the soma. The reaction product for electron microscopy is distributed throughout the cytoplasm, yet ultrastructural details are preserved. The sensory neurones that respond specifically to touch or pressure or noxious mechanical stimuli to the skin share in their branching pattern a number of common features. A single process arising from each cell body forms large primary branches that pass through the neuropil and leave the ganglion by the ipsilateral connectives and roots. Within the neuropil these branches give rise to numerous smaller secondary processes. In contrast, the annulus erector and large longitudinal motoneurones send their main process across the ganglion to bifurcate and enter the contralateral roots. Secondary processes of the motoneurones are highly branched and more numerous than those of the sensory cells. Each type of sensory and motor cell is distinguished by the shape, length and distribution of its secondary processes. Secondary processes of sensory neurones exhibit numerous swellings and irregularly shaped fingers. Electron micrographs show that the sensory neurones make synapses at these specializations, each of which contacts several postsynaptic processes. The sensory neurones receive inputs at the same fingers and swellings, an arrangement suggesting that regions within a cell’s arborization may function semi-autonomously. The main process and large branches of the two motor neurones are studded with spines a few micrometres long and a fraction of a micrometre in diameter. Vesicle-containing varicosities from other cells make synaptic contact primarily with the spines, which themselves have few vesicles. These two motor neurones are largely, if not entirely, postsynaptic to other neurones within the leech nervous system.


1981 ◽  
Vol 217 (1) ◽  
pp. 143-149 ◽  
Author(s):  
E.R. Macagno ◽  
K.J. Muller ◽  
W.B. Kristan ◽  
S.A. Deriemer ◽  
R. Stewart ◽  
...  

Development ◽  
1987 ◽  
Vol 100 (3) ◽  
pp. 479-487
Author(s):  
N. Stephens ◽  
N. Holder

The innervation of the biceps muscle was examined in regenerated and vitamin A-induced serially duplicated axolotl forelimbs using retrograde transport of horseradish peroxidase. The regenerated biceps muscle becomes innervated by motor neurones in the same position in the spinal cord as the normal biceps motor pool. In previous experiments in which the innervation of a second copy of a proximal limb muscle was examined in serially duplicated limbs (Stephens, Holder & Maden, 1985), the duplicate muscle was found to become innervated by motor neurones that would normally have innervated distal muscles. In the present study, the innervation of the second copy of biceps was examined under conditions designed to encourage nerve sprouting from ‘correct’ biceps axons. Following either partial limb denervation or denervation coupled with removal of the proximal biceps, the second copy of the muscle was still innervated by inappropriate motor neurones, which again would normally innervate distal limb muscles. These results are interpreted as evidence for the necessity for an appropriate local environment for axonal growth to allow reformation of a correct pattern of motor innervation in the regenerated limb.


1981 ◽  
Vol 93 (1) ◽  
pp. 133-147
Author(s):  
THOMAS A. CHRISTENSEN ◽  
ALBERT D. CARLSON

1. Male fireflies of the species Photuris versicolor produce a species-typical triple-pulsed flash which is used as a courtship signal. The neural anatomy was examined to determine if this complex behaviour could be attributed to the organization within the central nervous system. 2. The lantern is innervated primarily by the two most posterior abdominal ganglia. Bilateral roots from these ganglia form a symmetrical pattern of innervation to both sides of the lantern tissue. With minor exceptions, this pattern is similar to that described for other firefly species. 3. The neural organization within the lantern ganglia was determined by back-filling the roots with cobalt or Lucifer Yellow CH, and then examining the ganglia in whole mount. Clusters of three or four large dorsal unpaired median (DUM) neurone somata, each sending bilateral processes out of the lantern roots, were found in both lantern ganglia. 4. The DUM neurone axons bifurcate several times and ramify throughout the dorsal surface of the lantern tissue. More than one DUM neurone may innervate a particular region of photogenic tissue. 5. When dye was back-filled into peripheral branches of the lantern roots that do not innervate photogenic tissue, no DUM somata were stained. Instead, the fibres that filled carried the dye anteriorly up the nerve cord through the ipsilateral connective. No fibres were observed to cross the ganglion midline or exit from the contralateral root, nor were any fibres stained in the contralateral connectives. 6. DUM neurones within the lantern ganglia have resting potentials between 30 and 45 mv and they exhibit multiple, as well as single-peaked spontaneous action potentials. The presence of multiple spikes might reflect the special bilateral morphology of these neurones. 7. The lantern nervous system is organized in an arrangement capable of synchronizing the excitation of all the lantern photocytes. This neural organization could aid in the control of the complex flash pattern displayed by male Photuris versicolor fireflies.


1991 ◽  
Vol 39 (11) ◽  
pp. 1579-1583 ◽  
Author(s):  
L Nonnotte ◽  
A Buisson ◽  
F Nagy ◽  
M Moulins

We have developed a new double labeling method for electron microscopy to characterize selectively two physiologically identified neurons on the same preparation. The stomatogastric nervous system of crustaceans was used to test the distinguishing staining characteristics of the two labels. Neurons were labeled on one side with horseradish peroxidase (HRP) and on the other side with Lucifer yellow (LY). After blue light irradiation of the tissue in the presence of diaminobendizine, the two labeled neurons could be easily observed and discriminated on the same section by the two different reaction products. This simple technique of double labeling is useful in experimental neuroanatomy for the detailed study of synaptic relationships.


1984 ◽  
Vol 110 (1) ◽  
pp. 69-90 ◽  
Author(s):  
A. N. SPENCER ◽  
S. A. ARKETT

1. Two discrete networks of neurones in the outer nerve-ring of Polyorchis penicillatus can be identified by their physiological and morphological characteristics. 2. The ‘B’ system is characterized by the regular, spontaneous firing pattern that can be recorded intracellularly. Bursts of up to six spikes are produced in response to a rapid reduction in the light intensity. 3. Neurones of the ‘B’ system are electrically coupled to one another. 4. Action potentials in the ‘B’ system produce unitary EPSPs in swimming motor neurones and in epithelial cells overlying the outer nerve-ring. 5. Lucifer Yellow injected into a ‘B’ neurone diffuses rapidly through neighbouring neurones to reveal a condensed network of neurones in the centre of the nerve-ring and a more diffuse network passing up and around each tentacle. 6. The ‘O’ system is characterized by very regular (approx. 1 Hz), spontaneous membrane potential oscillations. Action potentials are never recorded. 7. Neurones of the ‘O’ system are electrically coupled to one another. 8. There is evidence of interaction between the ‘O’ system and swimming motor neurones. 9. Lucifer Yellow injected into an ‘O’ neurone diffuses through member neurones to show an anastomosing network of neurones extending across the width of the outer nerve-ring and tracts of neurones extending up the sides of each tentacle towards the ocelli. 10. The restriction of injected Lucifer Yellow to each of the networks and the blockade of interaction between systems by Mg2+ anaesthesia are evidence that signalling between different central networks is by chemical means. 11. The adaptive advantages of this type of functional organization of central neurones in radially symmetrical animals are discussed. Such an organization is compared with that found in bilateral animals.


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