The Function and Fine Structure of the Cephalic Airflow Receptor in Schistocerca Gregaria

Electron micrographs of parts of the sense organ showed that the dendritic axis consisted of a large and a small envelope containing microtubules as their main inclusion. The envelopes are supported by a thick-walled tube believed to be part of the Ist-tier sheath cells. The small envelope is segregated from the large envelope near its apex by a fold of the tube wall. The packing of the neurotubular array within the small envelope is both more dense and more regular than within the large envelope. The tube is separated by an extracellular space from the trichogen-tormogen cell. Sections through the apex of the dendrite reveal a homogeneous cap unlikely to be part of a structure continued into the upper region of the hair shaft. No ciliary structures were visible within the dendrite, whose microtubules pass into the neuron cell body proximally. Sections through the neuron cell body reveal branched mitochondria, and numerous microtubules. Rates of discharge in sensory axons from these hair organs produced by deflexion of the hair shaft were found to be within the range 300-100 impulses/sec. There is an initial phase of rapid adaptation which gives place to a steady rate. It is suggested that the fine structure of the receptor may indicate mechano-electrical transduction at a more proximal level than is believed to be the case in some other types of receptor. The diaphragms that support the hair shaft laterally can be seen to be composed of fine cuticular strands.

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Observations on the Nervous System of the Flight Apparatus in the Locust Schistocerca Gregaria

Journal of Cell Science ◽

10.1242/jcs.s3-105.70.183 ◽

1964 ◽

Vol s3-105 (70) ◽

pp. 183-201

Author(s):

D. M. GUTHRIE

Keyword(s):

Nervous System ◽

Schistocerca Gregaria ◽

Sensory System ◽

Outer Region ◽

Hair Shaft ◽

Distal Process ◽

Motor Neurones ◽

The Central Nervous System ◽

Tormogen Cell ◽

Hair Shafts

The hair sense-organs of the head are part of a sensory system affecting the activity of motor neurones to the flight muscles. They possess curved hollow hair shafts inserted in a complex socket. A large neurone is present beneath the socket and is partly surrounded by a large formative cell, the trichogen-tormogen cell. The distal process passes up into the expanded base of the hair shaft. Fine connexions between the outer region of the formative cell and the inner part round the neurone process, possibly limiting angular sensitivity, can be seen in some specimens, although the form and fine structure of the hair shaft is almost certainly important in this respect. The axons from the 5 areas of hair organs are collected together into a dorsal tegumentary nerve, those from area three forming a short subocellar nerve. Electronmicrographs of this nerve show that there are a number of large fibres (1 to 5 µ), and many more smaller fibres (1.0 to 0.1µ.) with no sheaths. There were estimated to be 5,500 fibres in each dorsal tegumentary nerve. Within the central nervous system, the dorsal tegumentary fibres may follow one of 4 routes, as follows. They may (i) pass forward into the protocerebrum, (ii) end in zones of terminals in the deutocerebral region, (iii) a few thick fibres pass down into the suboesophageal ganglion and then cross over to the opposite side giving off collaterals before descending to the pterothoracic ganglia, (iv) most of the fine descending fibres probably end at the suboesophageal level, a proportion of them crossing over here. The motor neurones to the longitudinal indirect muscles M81 and M82 consist of 4 anterior and 1 posterior cell respectively, and possess large and striking cell bodies, whose collaterals could be seen in the dorsal zones of motor terminals. The probable internuncial links between the sensory and motor arcs are outlined.

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Regulation of motor neuron dendrite growth by NMDA receptor activation

Development ◽

10.1242/dev.120.11.3063 ◽

1994 ◽

Vol 120 (11) ◽

pp. 3063-3071 ◽

Cited By ~ 1

Author(s):

R.G. Kalb

Keyword(s):

Nmda Receptor ◽

Motor Neuron ◽

Cell Body ◽

Motor Neurons ◽

Receptor Activation ◽

Dendrite Growth ◽

Postnatal Life ◽

Receptor Antagonism ◽

Neuron Cell Body ◽

Early Postnatal Life

Spinal motor neurons undergo great changes in morphology, electrophysiology and molecular composition during development. Some of this maturation occurs postnatally when limbs are employed for locomotion, suggesting that neuronal activity may influence motor neuron development. To identify features of motor neurons that might be regulated by activity we first examined the structural development of the rat motor neuron cell body and dendritic tree labeled with cholera toxin-conjugated horseradish peroxidase. The motor neuron cell body and dendrites in the radial and rostrocaudal axes grew progressively over the first month of life. In contrast, the growth of the dendritic arbor/cell and number of dendritic branches was biphasic with overabundant growth followed by regression until the adult pattern was achieved. We next examined the influence of neurotransmission on the development of these motor neuron features. We found that antagonism of the N-methyl-D-aspartate (NMDA) subtype of glutamate receptor inhibited cell body growth and dendritic branching in early postnatal life but had no effect on the maximal extent of dendrite growth in the radial and rostrocaudal axes. The effects of NMDA receptor antagonism on motor neurons and their dendrites was temporally restricted; all of our anatomic measures of dendrite structure were resistant to NMDA receptor antagonism in adults. These results suggest that the establishment of mature motor neuron dendritic architecture results in part from dendrite growth in response to afferent input during a sensitive period in early postnatal life.

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Calcium Action Potential Induction in a “Nonexcitable” Motor Neuron Cell Body

Neural Mechanisms of Conditioning ◽

10.1007/978-1-4613-2115-6_18 ◽

1986 ◽

pp. 283-289

Author(s):

T. Shimahara ◽

G. Czternasty ◽

J. Stinnakre ◽

J. Bruner

Keyword(s):

Action Potential ◽

Motor Neuron ◽

Cell Body ◽

Neuron Cell Body ◽

Calcium Action Potential

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Translocation of the neuronal cytoskeleton and axonal locomotion

Philosophical Transactions of the Royal Society of London Series B Biological Sciences ◽

10.1098/rstb.1982.0135 ◽

1982 ◽

Vol 299 (1095) ◽

pp. 313-327 ◽

Cited By ~ 48

Keyword(s):

Plasma Membrane ◽

Axonal Transport ◽

Cell Body ◽

Cytoskeletal Proteins ◽

The Other ◽

Current Understanding ◽

Axonal Elongation ◽

Neuronal Cytoskeleton ◽

Other Hand ◽

Neuron Cell Body

Recent studies of axonal transport indicate that cytoskeletal proteins are assembled into polymers in the neuron cell body and that these polymers move from the cell body toward the end of the axon. On the other hand, membranous elements appear to be inserted into the axonal plasma membrane preferentially at the end of the axon. These new observations are explored in relation to our current understanding of axonal elongation.

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Fine structure of the dendritic junction body region of the antennal sensory cone in a larval elaterid (Coleoptera)

Canadian Journal of Zoology ◽

10.1139/z71-122 ◽

1971 ◽

Vol 49 (6) ◽

pp. 817-821 ◽

Cited By ~ 8

Author(s):

David A. Scott ◽

R. Y. Zacharuk

Keyword(s):

Fine Structure ◽

Basal Body ◽

Sense Organ ◽

Body Region ◽

Ultrastructural Evidence ◽

Primary Function ◽

Secretory Products

The component ciliary collar, basal body, ciliary rootlets, trichogen–dendrite secretory junctions and secretory inclusions of the junction body region of dendrites in the wireworm antennal sensory cone are described. The primary function ascribed to the junction body region, based on the ultrastructural evidence presented, is one of secretion. The hypothesis that the secretory products produced in the junction body region are transported to the dendritic terminations in the sense organ is discussed and supported.

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The fine morphology of the osphradial sense organs of the mollusca. III. Placophora and bivalvia

Philosophical Transactions of the Royal Society of London Series B Biological Sciences ◽

10.1098/rstb.1987.0002 ◽

1987 ◽

Vol 315 (1169) ◽

pp. 37-61 ◽

Cited By ~ 26

Keyword(s):

Fine Structure ◽

Sense Organ ◽

Mantle Cavity ◽

Sense Organs ◽

Physiological Evidence ◽

Anal Papillae ◽

Fine Morphology

The fine morphology of the osphradia of six placophorans and eight bivalves, representing all major subgroups of both classes, is described. In addition the branchial and lateral sense organs of Lepidopleurus cajetanus (Placophora) have been investigated ultrastrucurally. Whereas osphradial fine structure is very uniform within the Bivalvia there are differences between Ischnochitonina and Acanthochitonina, supporting the separation of both groups. Major differences in the conditions of the mantle cavity divide Recent Placophora into the orders Lepidopleurida and Chitonida. The homology of the molluscan osphradium throughout the phylum is discussed in detail. It is concluded that the terminal sense organ (Caudofoveata, Solenogastres), the adanal sensory stripes (Placophora—Chitonida), the interbranchial and post-anal papillae of Nautilus (Cephalopoda), and the organ of Lacaze (Gastropoda-Basommatophora) are homologous with the organs of Spengel (Prosobranchia, Opisthobranchia, Bivalvia), all to be called osphradial sense organs (or osphradia). After discussion it is concluded that the osphradium is a chemoreceptor and not a mechanoreceptor as suggested by many authors. This is shown by the physiological evidence so far reported but mainly by the existence of paddle cilia in the osphradial epithelia throughout the Mollusca, which are typical of molluscan chemoreceptors. It is suggested that the osphradium is primarily used in sexual biology (coordination of spawning, search for a mate), a role altered within the Gastropoda (search for food, osmoreceptor, p O2 -receptor).

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The architecture of the accessory reproductive glands of the desert locust IV. Fine structure of the glandular epithelium

Philosophical Transactions of the Royal Society of London Series B Biological Sciences ◽

10.1098/rstb.1969.0037 ◽

1969 ◽

Vol 256 (802) ◽

pp. 85-114 ◽

Cited By ~ 25

Keyword(s):

Fine Structure ◽

Phase Contrast ◽

Electron Microscope Study ◽

Schistocerca Gregaria ◽

Mirror Image ◽

Secretory Process ◽

Desert Locust ◽

Accessory Glands ◽

Accessory Reproductive Glands ◽

Gland Type

The male desert locust, Schistocerca gregaria , has two masses of thin glands, each mass containing 16 glands. The glands in each mass are arranged in a precise manner, which is a mirror image of the arrangement to be found in the other gland mass. They produce secretions which participate in the production of the spermatophore and most of its contents during mating. The fine structure of these glands is described in detail on the basis of an electron-microscope study of sectioned glands and their secretions. It is revealed that the characteristics of the glandular epithelia and their corresponding secretions lead to the division of the accessory glands into nine distinct types. This finding strengthens the recent division of the glands into nine types based on histological, histochemical, and phase-contrast features. One gland produces a proteinaceous, crystalline secretion (gland 1), three types of glands produce a minutely fibrous secretion (glands 2 and 4, and ‘homogeneous’ glands), three other gland types produce a globular secretion (glands 6, 11 and 12), and one gland type has a lipoid secretion (gland 3). Gland 16, the functional seminal vesicle, does not produce a recognizable secretion. The cytoplasmic organelles that are concerned in the secretory process, and the manner in which their development varies with each gland type, are discussed.

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Synchrony of cell spreading and contraction force as phagocytes engulf large pathogens

The Journal of Cell Biology ◽

10.1083/jcb.122.6.1295 ◽

1993 ◽

Vol 122 (6) ◽

pp. 1295-1300 ◽

Cited By ~ 58

Author(s):

E Evans ◽

A Leung ◽

D Zhelev

Keyword(s):

Cell Body ◽

Time Course ◽

Cell Spreading ◽

Contractile Force ◽

Contraction Force ◽

Physical Measurements ◽

Steady Rate ◽

Contractile Stress ◽

Major Increase

A simple micromechanical method has been used to directly measure the force of contraction in single mammalian phagocytes (blood granulocytes) during engulfment of large yeast pathogens. Both the time course of cell spreading over the yeast particle and increase in cell body contractile force were quantitated at three temperatures in the range of 23-35 degrees C. The surprising feature of the phagocyte response was that engulfment and cell body contraction occurred in a serial sequence: i.e., the phagocyte spread rapidly over the particle at a steady rate with no detectable cell body contraction; when spreading stopped, contraction force in the cell body then rose steadily to a plateau level that remained stationary until the next sequence of spreading and contraction. Both spreading and contraction exhibited abrupt start/stop kinetics. Also impressive, the cell contraction force stimulated by phagocytosis was quite large (approximately 10(-8) N)-two orders of magnitude larger than the force necessary to deform passive phagocytes to the same extent. If distributed uniformly over the cell cross section, the contraction force is equivalent to an average contractile stress of approximately 10(3) N/m2 (0.01 Atm). These physical measurements in situ set critical requirements for the mechanism of force generation in granulocytes, imply that a major increase in network cross-linking accompanies build-up in contractile force and that subsequent network dissolution is necessary for locomotion.

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