scholarly journals Respiratory gas levels interact to control ventilatory motor patterns in isolated locust ganglia

2019 ◽  
Author(s):  
Stav Talal ◽  
Amir Ayali ◽  
Eran Gefen
Keyword(s):  
Respiratory Control ◽  
Ventilation Rate ◽  
Motor Patterns ◽  
Tracheal System ◽  
Thoracic Ganglia ◽  
Motor Nerves ◽  
Summary Statement ◽  
Respiratory Gases ◽  
Gas Supply ◽  
Ventilatory Muscles

AbstractLarge insects actively ventilate their tracheal system even at rest, using abdominal pumping movements, which are controlled by a central pattern generator (CPG) in the thoracic ganglia. We studied the effects of respiratory gases on the ventilatory rhythm by isolating the thoracic ganglia and perfusing its main tracheae with various respiratory gas mixtures. Fictive ventilation activity was recorded from motor nerves controlling spiracular and abdominal ventilatory muscles. Both hypoxia and hypercapnia increased the ventilation rate, with the latter being much more potent. Sub-threshold hypoxic and hypercapnic levels were still able to modulate the rhythm as a result of interactions between the effects of the two respiratory gases. Additionally, changing the oxygen levels in the bathing saline affected ventilation rate, suggesting a modulatory role for haemolymph oxygen. Central sensing of both respiratory gases as well as interactions of their effects on the motor output of the ventilatory CPG reported here indicate convergent evolution of respiratory control among terrestrial animals of distant taxa.Summary statementTight control over respiratory gas supply to the isolated locust CNS reveals interactions of oxygen and carbon dioxide effects on central ventilatory output.

Pressure cycles and the water economy of insects

1988 ◽  
Vol 318 (1190) ◽  
pp. 377-407 ◽  
Keyword(s):  
Body Temperature ◽  
Water Exchange ◽  
Vapour Phase ◽  
The Body ◽  
Tracheal System ◽  
Water Economy ◽  
Insect Wings ◽  
Pressure Cycle ◽  
Respiratory Gases

Water exchange between insects and their environment via the vapour phase includes influx and efflux components. The pressure cycle theory postulates that insects (and some other arthropods) can regulate the relative rates of influx and efflux of water vapour by modulating hydrostatic pressures at a vapour-liquid interface by compressing or expanding a sealed, gas-filled cavity. Some such cavities, like the tracheal system, could be compressed by elevated pressure in all or part of the haemocoele. Others, perhaps including the muscular rectum of flea prepupae, could be compressed by intrinsic muscles. Maddrell Insect Physiol . 8, 199 (1971)) suggested a pressure cycle mechanism of this kind to account for rectal uptake of water vapour in Thermobia but did not find it compatible with quantitative information then available. Newer evidence conforms better with the proposed mechanism. Cyclical pressure changes are of widespread occurrence in insects and have sometimes been shown to depend on water status. Evidence is reviewed for the role of the tracheal system as an avenue for net exchange of water between the insect and its environment. Because water and respiratory gases share common pathways, most published findings fail to distinguish between the conventional view that the tracheal system has evolved as a site for distribution and exchange of respiratory gases and that any water exchange occurring in it is generally incidental and nonadaptive, and the theory proposed here. The pressure cycle theory offers a supplementary explanation not incompatible with evidence so far available. The relative importance of water economy and respiratory exchange in the functioning of compressible cavities such as the tracheal system remains to be explored. Some further implications of the pressure cycle theory are discussed. Consideration is given to the possible involvement of vapour-phase transport in the internal redistribution of water within the body. It is suggested that some insect wings may constitute internal vapour-liquid exchange sites, where water can move from the body fluids to the intratracheal gas. Ambient and body temperature must influence rates of vapour-liquid mass transfer. If elevated body temperature promotes evaporative discharge of the metabolic water burden that has been shown to accumulate during flight in some large insects, their minimum threshold thoracic temperature for sustained flight may relate to the maintenance of water balance. The role of water economy in the early evolution of insect wings is considered. Pressure cycles might help to maintain water balance in surface-breathing insects living in fresh and saline waters, but the turbulence of the surface of the open sea might prevent truly marine forms from using this mechanism.

scholarly journals Convergence of inhibitory neural inputs regulate motor activity in the murine and monkey stomach

2016 ◽  
Vol 311 (5) ◽  
pp. G838-G851 ◽  
Author(s):  
Lara A. Shaylor ◽  
Sung Jin Hwang ◽  
Kenton M. Sanders ◽  
Sean M. Ward
Keyword(s):  
Nitric Oxide ◽  
Motor Activity ◽  
Motor Neurons ◽  
Electrical Field Stimulation ◽  
Neural Responses ◽  
Motor Patterns ◽  
Primate Model ◽  
Distal Stomach ◽  
Gastric Motor Activity ◽  
Motor Nerves

Inhibitory motor neurons regulate several gastric motility patterns including receptive relaxation, gastric peristaltic motor patterns, and pyloric sphincter opening. Nitric oxide (NO) and purines have been identified as likely candidates that mediate inhibitory neural responses. However, the contribution from each neurotransmitter has received little attention in the distal stomach. The aims of this study were to identify the roles played by NO and purines in inhibitory motor responses in the antrums of mice and monkeys. By using wild-type mice and mutants with genetically deleted neural nitric oxide synthase ( Nos1 −/−) and P2Y1 receptors ( P2ry1 −/−) we examined the roles of NO and purines in postjunctional inhibitory responses in the distal stomach and compared these responses to those in primate stomach. Activation of inhibitory motor nerves using electrical field stimulation (EFS) produced frequency-dependent inhibitory junction potentials (IJPs) that produced muscle relaxations in both species. Stimulation of inhibitory nerves during slow waves terminated pacemaker events and associated contractions. In Nos1 −/− mice IJPs and relaxations persisted whereas in P2ry1 −/− mice IJPs were absent but relaxations persisted. In the gastric antrum of the non-human primate model Macaca fascicularis, similar NO and purine neural components contributed to inhibition of gastric motor activity. These data support a role of convergent inhibitory neural responses in the regulation of gastric motor activity across diverse species.

Dynamics of tracheal compression in the horned passalus beetle

2013 ◽  
Vol 304 (8) ◽  
pp. R621-R627 ◽  
Author(s):  
James S. Waters ◽  
Wah-Keat Lee ◽  
Mark W. Westneat ◽  
John J. Socha
Keyword(s):  
Dynamical Behavior ◽  
The Body ◽  
Reverse Direction ◽  
Effective Diameter ◽  
Contrast Imaging ◽  
Tracheal System ◽  
Tracheal Compression ◽  
Internal Mixing ◽  
Respiratory Gases ◽  
Opening And Closing

Rhythmic patterns of compression and reinflation of the thin-walled hollow tubes of the insect tracheal system have been observed in a number of insects. These movements may be important for facilitating the transport and exchange of respiratory gases, but observing and characterizing the dynamics of internal physiological systems within live insects can be challenging due to their size and exoskeleton. Using synchrotron X-ray phase-contrast imaging, we observed dynamical behavior in the tracheal system of the beetle, Odontotaenius disjunctus. Similar to observations of tracheal compression in other insects, specific regions of tracheae in the thorax of O. disjunctus exhibit rhythmic collapse and reinflation. During tracheal compression, the opposing sides of a tracheal tube converge, causing the effective diameter of the tube to decrease. However, a unique characteristic of tracheal compression in this species is that certain tracheae collapse and reinflate with a wavelike motion. In the dorsal cephalic tracheae, compression begins anteriorly and continues until the tube is uniformly flattened; reinflation takes place in the reverse direction, starting with the posterior end of the tube and continuing until the tube is fully reinflated. We report the detailed kinematics of this pattern as well as additional observations that show tracheal compression coordinated with spiracle opening and closing. These findings suggest that tracheal compression may function to drive flow within the body, facilitating internal mixing of respiratory gases and ventilation of distal regions of the tracheal system.

Invited Review: Neuroplasticity in respiratory motor control

2003 ◽  
Vol 94 (1) ◽  
pp. 358-374 ◽  
Author(s):  
Gordon S. Mitchell ◽  
Stephen M. Johnson
Keyword(s):  
Control System ◽  
Neural Control ◽  
Developmental Plasticity ◽  
Biological Significance ◽  
Respiratory Control ◽  
System A ◽  
Cord Injury ◽  
Respiratory Plasticity ◽  
Considerable Work ◽  
Respiratory Gases

Although recent evidence demonstrates considerable neuroplasticity in the respiratory control system, a comprehensive conceptual framework is lacking. Our goals in this review are to define plasticity (and related neural properties) as it pertains to respiratory control and to discuss potential sites, mechanisms, and known categories of respiratory plasticity. Respiratory plasticity is defined as a persistent change in the neural control system based on prior experience. Plasticity may involve structural and/or functional alterations (most commonly both) and can arise from multiple cellular/synaptic mechanisms at different sites in the respiratory control system. Respiratory neuroplasticity is critically dependent on the establishment of necessary preconditions, the stimulus paradigm, the balance between opposing modulatory systems, age, gender, and genetics. Respiratory plasticity can be induced by hypoxia, hypercapnia, exercise, injury, stress, and pharmacological interventions or conditioning and occurs during development as well as in adults. Developmental plasticity is induced by experiences (e.g., altered respiratory gases) during sensitive developmental periods, thereby altering mature respiratory control. The same experience later in life has little or no effect. In adults, neuromodulation plays a prominent role in several forms of respiratory plasticity. For example, serotonergic modulation is thought to initiate and/or maintain respiratory plasticity following intermittent hypoxia, repeated hypercapnic exercise, spinal sensory denervation, spinal cord injury, and at least some conditioned reflexes. Considerable work is necessary before we fully appreciate the biological significance of respiratory plasticity, its underlying cellular/molecular and network mechanisms, and the potential to harness respiratory plasticity as a therapeutic tool.

On a New Type of Respiratory Interrelation between an Insect (Chalcid) Parasite and its Host (Coccidae)

Parasitology ◽  
1936 ◽  
Vol 28 (4) ◽  
pp. 517-540 ◽  
Author(s):  
W. H. Thorpe
Keyword(s):  
Instar Larva ◽  
Scale Insect ◽  
Basement Membranes ◽  
Injection Technique ◽  
Functional Communication ◽  
Tracheal System ◽  
Larval Instars ◽  
History Of ◽  
New Type ◽  
Respiratory Gases

1. The life history of Encyrtus (Comys) infelix (Embleton), a hymenopterous parasite belonging to the chalcid family Encyrtidae, is described. It parasitises Saissetia hemisphaerica, a member of the subfamily Lecaniinae (Homoptera Coccidae). Its respiratory relationships with the host are of a quite extraordinary character.2. The egg is provided with a hollow stalk which is left protruding from the posterior dorsal body wall of the host. The first three larval instars are metapneustic, the spiracles being placed at the tip of a pair of long caudal processes which are inserted in the hollow stalk. It has been proved that these spiracles are open and in actual communication with the atmospheric air, which enters through the pedicel.3. The fourth and fifth larval instars are amphipneustic and the manner of respiration is entirely changed. The caudal processes degenerate and finally break away. The fourth instar larva turns round in the scale insect and becomes invested with a closely fitting transparent membraneous sheath produced by the phagocytes and fine tracheal branches of the host. This process appears to be merely a special case of the type of phagocytic activity which normally gives rise to the basement membranes and “connective tissue” membranes; such membranes are particularly conspicuous and well developed in Saissetia. The sheath becomes attached in an extraordinary manner to the main lateral tracheal trunks of the host in four (or six) places in the neighbourhood of the larval spiracles. This process is described in detail. It has been proved by an injection technique that an actual connection is established between the lumen of the host trachea and the cavity of the sheath. Bubbles of gas appear inside the sheath close to the points of attachment and near the spiracles of the larva which are thus put into functional communication with the tracheal system of the host.4. While the production of the sheath might under certain circumstances be of value to the host the development of tracheal attachments appears to be of value to the parasite alone. The conclusion that the whole structure is an adaptation for the respiration of the parasite seems inescapable. A theory is tentatively put forward to account for the stimulation of the host tracheal epithelium by a sudden physiological change in the tension of the respiratory gases in the region of the parasite spiracles.5. References to similar instances among the Chalcids are briefly reviewed. It is suggested that the “puparia” which have been described in the case of one or two other Chalcidoidea may be found to arise in the same way.

Central input to primary afferent neurons in crayfish, Pacifastacus leniusculus, is correlated with rhythmic motor output of thoracic ganglia

1986 ◽  
Vol 55 (4) ◽  
pp. 678-688 ◽  
Author(s):  
K. T. Sillar ◽  
P. Skorupski
Keyword(s):  
Motor Neurons ◽  
Motor Pattern ◽  
Reversal Potential ◽  
Motor Output ◽  
Resting Membrane Potential ◽  
Strongly Correlated ◽  
Motor Patterns ◽  
Thoracic Ganglia ◽  
Rhythmic Motor ◽  
Receptor Organ

A preparation is described in which the thoracic ganglia of the crayfish are isolated together with the thoracocoxal muscle receptor organ (TCMRO) of the fourth leg. This preparation allows intracellular analysis of both centrally generated and reflex activity in leg motor neurons (MNs). The isolated thoracic ganglia can spontaneously generate a rhythmic motor pattern resembling that used during forward walking (Fig. 4). This involves the reciprocal activity of promotor and remotor MNs, with levator MNs firing in phase with promotor bursts. Stretch of the TCMRO in quiescent preparations evokes a resistance reflex in promotor MNs (Fig. 6). In more active preparations the response is variable and often becomes an assistance reflex, with excitation of remotor MNs on stretch (Fig. 7). When rhythmic motor patterns occur, the neuropilar processes of the S and T fibers receive central inputs that are strongly correlated with the oscillatory drive to the MNs and probably have the same origin (Figs. 8 and 9). Central inputs to the S and T fibers occur in opposite phases within a cycle of rhythmic motor output. The S fiber is depolarized in phase with promotor MNs and the T fiber in phase with remotor activity. The input to the T fiber is shown to be a chemical synaptic drive that has a reversal potential approximately 14 mV more depolarized than the fiber's resting membrane potential. This input substantially modulates the amplitude and waveform of passively propagated receptor potentials generated by TCMRO stretch (Fig. 11). It is argued that the central inputs to the TCMRO afferents will modulate proprioceptive feedback resulting from voluntary movements.

Synaptic connections between motor neurons and interneurons in the fourth thoracic ganglion of the crayfish, Procambarus clarkii

1989 ◽  
Vol 62 (6) ◽  
pp. 1237-1250 ◽  
Author(s):  
A. Chrachri ◽  
F. Clarac
Keyword(s):  
Motor Neurons ◽  
Cobalt Chloride ◽  
Procambarus Clarkii ◽  
Lucifer Yellow ◽  
Motor Nerve ◽  
Thoracic Ganglion ◽  
Synaptic Connections ◽  
Motor Patterns ◽  
Antagonist Muscles ◽  
Motor Nerves

1. A new preparation of the thoracic nervous system of the crayfish, Procambarus clarkii, has been developed, in which it is possible to work with identified members of motor neuronal pools. 2. In such a preparation, it is possible to dissect all specific proximal motor nerves (protractor, retractor, anterior elevator, posterior elevator, and depressor). Motor neurons innervating the four proximal muscles of the fourth walking leg have been identified both physiologically and anatomically by staining the recorded motor neuron with Lucifer yellow through the microelectrode. 3. By the use of cobalt chloride, we have mapped the distribution of somata of all motor neurons within the fourth thoracic ganglion that innervate the different groups of muscles controlling the movement of the fourth walking leg. 4. Most motor neurons innervating the same muscle seem to be electrically coupled, except some depressor motor neurons. 5. Motor neurons innervating antagonist muscles are linked by inhibitory connections. These connections are reciprocal for protractor and retractor motor neurons but usually not reciprocal between elevator and depressor motor neurons. 6. Walking interneurons were identified as neurons without axons in any motor nerve, which modified the motor neuronal activity. Some of them have been injected with Lucifer yellow. 7. Some interneurons make synaptic connections only with antagonist motor neurons that control the movement of one joint. Probably their functional role is to reinforce or to limit the antagonism between each pair of antagonist motor neurons. 8. Other interneurons make synaptic connections with motor neurons innervating muscles controlling different leg joints. These interneurons may play a role in generating the motor patterns that underlie forward and backward walking.

Nitric oxide induces centrally generated motor patterns in the locust suboesophageal ganglion

2001 ◽  
Vol 204 (21) ◽  
pp. 3789-3801
Author(s):  
Georg F. Rast
Keyword(s):  
Nitric Oxide ◽  
Cyclic Gmp ◽  
Motor Pattern ◽  
Specific Inhibitor ◽  
Pattern Generation ◽  
Target Cells ◽  
Muscarinic Agonists ◽  
Motor Patterns ◽  
No Donor ◽  
Motor Nerves

SUMMARY The stimulatory effects of nitric oxide (NO) on central motor pattern generation in isolated locust suboesophageal ganglia (SOGs) were studied using extracellular recordings from motor nerves. Different NO donor molecules and a specific inhibitor of soluble guanylyl cyclases were used to confirm that the observed motor pattern occurred in response to activation of the NO/cyclic GMP signalling pathway. Experiments with muscarinic agonists and antagonists showed that the NO-induced motor pattern is generated independently from the motor pattern induced by muscarinic agonists described previously. Staining for NADPH-diaphorase and an antiserum directed against cyclic GMP were used to identify neurones representing potential sources of NO and their target cells within the SOG. Using intracellular dye injection and backfilling of peripheral nerves in combination with anti-cGMP immunohistochemistry, it was shown that identified efferent neurones involved in the mandibular motor pattern are potential target cells of NO.

scholarly journals How vocal temporal parameters develop: a comparative study between humans and songbirds, two distantly related vocal learners

2020 ◽  
Author(s):  
Miki Takahasi ◽  
Kazuo Okanoya ◽  
Reiko Mazuka
Keyword(s):  
Developmental Process ◽  
Developmental Change ◽  
Vocal Learning ◽  
Respiratory Control ◽  
Motor Patterns ◽  
Human Infants ◽  
Infant Cry ◽  
Human Speech ◽  
Temporal Parameters ◽  
Species Specific

Abstract Human infants acquire motor patterns for speech during the first several years of their lives. Sequential vocalizations such as human speech are complex behaviors, and the ability to learn new vocalizations is limited to only a few animal species. Vocalizations are generated through the coordination of three types of organs: namely, vocal, respiratory, and articulatory organs. Moreover, sophisticated temporal respiratory control might be necessary for sequential vocalization involving human speech. However, it remains unknown how coordination develops in human infants and if this developmental process is shared with other vocal learners. To answer these questions, we analyzed temporal parameters of sequential vocalizations during the first year in human infants and compared these developmental changes to song development in the Bengalese finch, another vocal learner. In human infants, early cry was also analyzed as an innate sequential vocalization. The following three temporal parameters of sequential vocalizations were measured: note duration (ND), inter-onset interval, and inter-note interval (INI). The results showed that both human infants and Bengalese finches had longer INIs than ND in the early phase. Gradually, the INI and ND converged to a similar range throughout development. While ND increased until 6 months of age in infants, the INI decreased up to 60 days posthatching in finches. Regarding infant cry, ND and INI were within similar ranges, but the INI was more stable in length than ND. In sequential vocalizations, temporal parameters developed early with subsequent articulatory stabilization in both vocal learners. However, this developmental change was accomplished in a species-specific manner. These findings could provide important insights into our understanding of the evolution of vocal learning.

scholarly journals Analysis of the Scaphognathite Ventilatory Pump in the Shore Crab Carcinus Maenas: I. WORK AND POWER

1984 ◽  
Vol 113 (1) ◽  
pp. 55-68 ◽  
Author(s):  
A. JOFFRE MERCIER ◽  
JERREL L. WILKENS
Keyword(s):  
Carcinus Maenas ◽  
Pattern Generator ◽  
Ventilation Rate ◽  
Isometric Tension ◽  
Shore Crab ◽  
Stroke Work ◽  
First Approximation ◽  
Gill Ventilation ◽  
Ventilation Rates ◽  
Ventilatory Muscles

Measurements of branchial pressure and ventilation volumes were used to calculate the work and power of gill ventilation in Carcinus maenas, during spontaneous as well as forced unilateral ventilation. With increasing ventilation rate (fR), the stroke work increases as a result of an elevated gradient of branchial pressure, while power output increases as a result of enhancement of both the pressure gradient and the flow rate. To a first approximation, the stroke work is proportional to fR1.5, and the power out-put is proportional to fR2.5. The available evidence suggests that flow is mainly laminar through the branchial chamber but turbulent through the pumping chamber. Evidence is presented which suggests that the crab is able to vary the resistance to the flow of branchial water. The increased branchial pressure at elevated ventilation rates constitutes an increased load on the ventilatory muscles. Measurements of isometric tension confirm that the muscles compensate for this increased load by generating greater force. Electromyograms support the notion that the change in force results from appropriate changes in the output from the central pattern generator.

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