scholarly journals Distribution of Intersegmental Interneurones That Can Reset the Respiratory Rhythm of the Locust

1989 ◽  
Vol 141 (1) ◽  
pp. 151-176 ◽  
Author(s):  
J. M. RAMIREZ ◽  
K.G. PEARSON
Keyword(s):  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Rate Increase ◽  
Respiratory Rhythm ◽  
Abdominal Ganglion ◽  
Suboesophageal Ganglion ◽  
Active Components ◽  
Rhythm Generator ◽  
Metathoracic Ganglion ◽  
Staining Techniques

Interneurones in the respiratory rhythm generator of the locust were identified by means of intracellular recording and staining techniques. A description is made of the properties and structures of nine intersegmental neurones which reset the respiratory rhythm when injected with current pulses. All but one of these neurones discharged in phase with expiration. The injection of constant depolarizing current into these interneurones altered the respiratory rate (increase for six, decrease for three). The respiratory rhythm generator extends more posteriorly within the ventral nerve cord than the metathoracic ganglion. In the first fused abdominal ganglion, four individual interneurones were identified descending into the unfused abdominal ganglia. In the first unfused abdominal ganglion an intemeurone which reset the respiratory rhythm was found ascending into the metathoracic ganglion. The respiratory rhythm generator also extends more anteriorly within the ventral nerve cord than the metathoracic ganglion. Two interneurones influencing the respiratory rhythm send their axons from the first fused abdominal ganglion into the meta- and mesothoracic ganglia. One of these directly excited a mesothoracic intemeurone which also influenced the respiratory rhythm when injected with current. In the suboesophageal ganglion another intemeurone was found which, although capable of resetting the respiratory rhythm, was not alway active during respiration. We conclude that the respiratory rhythm generator is distributed over abdominal, thoracic and suboesophageal ganglia. At least one part of the respiratory rhythm generator (in the suboesophageal ganglion) is not always active and can be recruited during vigorous respiration. Thus the number of active components in the respiratory rhythm generator is variable and additional elements can be recruited depending on the behavioural situation.

THE HISTOLOGY OF THE GIANT FIBRE SYSTEM IN THE ABDOMINAL VENTRAL NERVE CORD OF THE DESERT LOCUST

1970 ◽  
Vol 102 (9) ◽  
pp. 1163-1168 ◽  
Author(s):  
W. D. Seabrook
Keyword(s):  
Single Cell ◽  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Schistocerca Gregaria ◽  
Desert Locust ◽  
Giant Fibre ◽  
Metathoracic Ganglion ◽  
Giant Fibres ◽  
Giant Fibre System

AbstractSchistocerca gregaria possess four neurones of giant fibre proportions within the abdominal ventral nerve cord. These fibres arise from single cell bodies in the terminal ganglionic mass and pass without interruption to the metathoracic ganglion. Fibres become reduced in diameter when passing through a ganglion. Branching of the giant fibres occurs in abdominal ganglia 6 and 7.

Reconfiguration of the Respiratory Network at the Onset of Locust Flight

1998 ◽  
Vol 80 (6) ◽  
pp. 3137-3147 ◽  
Author(s):  
Jan-Marino Ramirez
Keyword(s):  
Respiratory Activity ◽  
Respiratory Rhythm ◽  
Quiescent State ◽  
Suboesophageal Ganglion ◽  
Rhythm Generator ◽  
Locust Flight ◽  
Respiratory Network ◽  
Intracellular Stimulation ◽  
Tonic Stimulation ◽  
Stimulation Of

Ramirez, Jan-Marino. Reconfiguration of the respiratory network at the onset of locust flight. J. Neurophysiol. 80: 3137–3147, 1998. The respiratory interneurons 377, 378, 379 and 576 were identified within the suboesophageal ganglion (SOG) of the locust. Intracellular stimulation of these neurons excited the auxillary muscle 59 (M59), a muscle that is involved in the control of thoracic pumping in the locust. Like M59, these interneurons did not discharge during each respiratory cycle. However, the SOG interneurons were part of the respiratory rhythm generator because brief intracellular stimulation of these interneurons reset the respiratory rhythm and tonic stimulation increased the frequency of respiratory activity. At the onset of flight, the respiratory input into M59 and the SOG interneurons was suppressed, and these neurons discharged in phase with wing depression while abdominal pumping movements remained rhythmically active in phase with the slower respiratory rhythm (Fig. 9 ). The suppression of the respiratory input during flight seems to be mediated by the SOG interneuron 388. This interneuron was tonically activated during flight, and intracellular current injection suppressed the respiratory rhythmic input into M59. We conclude that the respiratory rhythm generator is reconfigured at flight onset. As part of the rhythm-generating network, the interneurons in the SOG are uncoupled from the rest of the respiratory network and discharge in phase with the flight rhythm. Because these SOG interneurons have a strong influence on thoracic pumping, we propose that this neural reconfiguration leads to a behavioral reconfiguration. In the quiescent state, thoracic pumping is coupled to the abdominal pumping movements and has auxillary functions. During flight, thoracic pumping is coupled to the flight rhythm and provides the major ventilatory movements during this energy-demanding locomotor behavior.

scholarly journals Synaptic transmission of nervous impulses through the last abdominal ganglion of the cockroach

1937 ◽  
Vol 122 (826) ◽  
pp. 106-118 ◽  
Keyword(s):  
Synaptic Transmission ◽  
Nerve Cord ◽  
Action Potentials ◽  
Ventral Nerve Cord ◽  
Abdominal Ganglion ◽  
Acoustic Stimuli ◽  
Excellent Opportunity ◽  
Random Activity ◽  
Previous Communication

In a previous communication (1936) we have described the response of the cereal nerve of the cricket when the cercus is subjected to acoustic stimuli. In the course of that work we attempted to trace the afferent fibres to their destination by recording from the ventral nerve cord at various levels anterior to the last abdominal ganglion. It was immediately apparent that, while some of the fibres from the acoustically sensitive end-organs of the cercus ran directly through the ganglion and up the cord, others terminated in the ganglion in synaptic relation with a relatively small number of fibres running forwards in the cord and yielding action potentials of considerable magnitude. Contrary to expectation we found that, subject to certain conditions noted below, the random activity in the abdominal nerve cord was never large enough to obscure the wanted signals, and it seemed to us that the preparation offered an excellent opportunity for an examination of the properties of a central nervous synapse. This paper describes the results of this examination.

scholarly journals Unpaired Median Neurones in a Lepidopteran Larva (Antheraea Pernyi): I. Anatomy and Physiology

1988 ◽  
Vol 136 (1) ◽  
pp. 311-332 ◽  
Author(s):  
S. J. BROOKES ◽  
R. G. DE WEEVERS
Keyword(s):  
Nerve Cord ◽  
Action Potentials ◽  
Ventral Nerve Cord ◽  
Intracellular Recordings ◽  
Suboesophageal Ganglion ◽  
Antheraea Pernyi ◽  
Anatomy And Physiology ◽  
Branching Patterns ◽  
The Common ◽  
Synaptic Drive

The anatomy and physiology of two unpaired median neurones (MC1 and MC2) with bilaterally symmetrical axons in abdominal ganglia 3, 4, 5 and 6 of Antheraea pernyi larvae were studied. Intracellular dye filling of MC1 and MC2 revealed that they were distinguishable from all other neurones in the ganglia and that they both had axons projecting out of the ganglia in right and left nerves 1. The two cells were identical in their central anatomy and physiology, but could be distinguished from one another by their peripheral branching patterns. The significance of these patterns was investigated by detailed study of the neural and muscular anatomy of the proleg-bearing segments 3, 4, 5 and 6. The peripheral axons of MC1 and MC2 were exclusively associated with nerve trunks that could be traced to blocks of muscle. Intracellular recordings of the two median cells characteristically showed overshooting soma action potentials that were followed by a long afterhyperpolarization lasting many seconds. Simultaneous recordings from median cells in the same ganglion revealed that MC1 and MC2 shared an excitatory synaptic drive that largely determined their patterns of firing. Recordings from median cells in different ganglia showed that the common synaptic drive was also shared by median cells in different segments. Selective lesions of the ventral nerve cord indicated that the synaptic drive to MC1 and MC2 originated in the suboesophageal ganglion. These cells were similar in anatomy and physiology to the median cells in several other insects.

Extracellular filaments in the perineurium of the florida lobster, Panulirus argus

1987 ◽  
Vol 45 ◽  
pp. 784-785
Author(s):  
Roy J. Baerwald ◽  
Lura C. Williamson
Keyword(s):  
Blood Brain Barrier ◽  
Glial Cells ◽  
Tannic Acid ◽  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Florida Keys ◽  
Panulirus Argus ◽  
Brain Barrier ◽  
Cacodylate Buffer ◽  
Nerve Cords

In arthropods the perineurium surrounds the neuropile, consists of modified glial cells, and is the morphological basis for the blood-brain barrier. The perineurium is surrounded by an acellular neural lamella, sometimes containing scattered collagen-like fibrils. This perineurial-neural lamellar complex is thought to occur ubiquitously throughout the arthropods. This report describes a SEM and TEM study of the sheath surrounding the ventral nerve cord of Panulirus argus.Juvenile P. argus were collected from the Florida Keys and maintained in marine aquaria. Nerve cords were fixed for TEM in Karnovsky's fixative and saturated tannic acid in 0.1 M Na-cacodylate buffer, pH = 7.4; post-fixed in 1.0% OsO4 in the same buffer; dehydrated through a graded series of ethanols; embedded in Epon-Araldite; and examined in a Philips 200 TEM. Nerve cords were fixed for SEM in a similar manner except that tannic acid was not used.

scholarly journals Mutations Affecting Nerve Attachment of Caenorhabditis elegans

Genetics ◽  
2001 ◽  
Vol 157 (4) ◽  
pp. 1611-1622 ◽  
Author(s):  
Go Shioi ◽  
Michinari Shoji ◽  
Masashi Nakamura ◽  
Takeshi Ishihara ◽  
Isao Katsura ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Body Wall ◽  
The Body ◽  
Genetic Loci ◽  
Muscle Attachment ◽  
C Elegans ◽  
Ventral Cord ◽  
Excretory Canal

Abstract Using a pan-neuronal GFP marker, a morphological screen was performed to detect Caenorhabditis elegans larval lethal mutants with severely disorganized major nerve cords. We recovered and characterized 21 mutants that displayed displacement or detachment of the ventral nerve cord from the body wall (Ven: ventral cord abnormal). Six mutations defined three novel genetic loci: ven-1, ven-2, and ven-3. Fifteen mutations proved to be alleles of previously identified muscle attachment/positioning genes, mup-4, mua-1, mua-5, and mua-6. All the mutants also displayed muscle attachment/positioning defects characteristic of mua/mup mutants. The pan-neuronal GFP marker also revealed that mutants of other mua/mup loci, such as mup-1, mup-2, and mua-2, exhibited the Ven defect. The hypodermis, the excretory canal, and the gonad were morphologically abnormal in some of the mutants. The pleiotropic nature of the defects indicates that ven and mua/mup genes are required generally for the maintenance of attachment of tissues to the body wall in C. elegans.

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