Heat Shock–Mediated Thermoprotection of Larval Locomotion Compromised by Ubiquitous Overexpression of Hsp70 in Drosophila melanogaster

2005 ◽  
Vol 94 (5) ◽  
pp. 3563-3572 ◽  
Author(s):  
Markus K. Klose ◽  
David Chu ◽  
Chengfeng Xiao ◽  
Laurent Seroude ◽  
R. Meldrum Robertson
Keyword(s):  
Heat Shock ◽  
Sensory Feedback ◽  
Body Wall ◽  
Molecular Genetic ◽  
Pattern Generator ◽  
Sensory Function ◽  
Motor Patterns ◽  
Behavioral Techniques ◽  
Excitatory Junction Potentials ◽  
Body Wall Muscles

Maintaining the competence of locomotor circuitry under stressful conditions can benefit organisms by enabling locomotion to more tolerable microhabitats. We show that prior heat shock protects locomotion and the locomotor central pattern generator of larval Drosophila against subsequent hyperthermic stress. We combined molecular genetic, electrophysiological, and behavioral techniques to investigate heat shock–mediated thermoprotection. Prior heat shock increased the distance traveled by larvae during hyperthermia before failure. The frequency of the rhythm of peristaltic locomotor contractions and the velocity of locomotion were both less thermosensitive after heat shock and were less susceptible to failure at high temperatures. Rhythmic coordinated motor patterns, recorded intracellularly as excitatory junction potentials in body wall muscles of dissected preparations, were centrally generated because patterns could still be generated in the absence of sensory feedback (sensory function disrupted with shibire). Prior heat shock protected central circuit operation during hyperthermic stress by increasing the temperature at which it failed. Overexpression of Hsp70 after a heat shock using transgenic flies ( traII) did not enhance thermoprotection, as expected, but had deleterious effects on parameters of behavior.

scholarly journals The central pattern generator underlying swimming in Dendronotus iris: a simple half-center network oscillator with a twist

2016 ◽  
Vol 116 (4) ◽  
pp. 1728-1742 ◽  
Author(s):  
Akira Sakurai ◽  
Paul S. Katz
Keyword(s):  
Central Pattern Generator ◽  
Body Wall ◽  
Impulse Activity ◽  
Motor Pattern ◽  
Pattern Generator ◽  
Excitatory Synapse ◽  
Dynamic Clamp ◽  
Motor Patterns ◽  
The Brain ◽  
Excitatory Drive

The nudibranch mollusc, Dendronotus iris, swims by rhythmically flexing its body from left to right. We identified a bilaterally represented interneuron, Si3, that provides strong excitatory drive to the previously identified Si2, forming a half-center oscillator, which functions as the central pattern generator (CPG) underlying swimming. As with Si2, Si3 inhibited its contralateral counterpart and exhibited rhythmic bursts in left-right alternation during the swim motor pattern. Si3 burst almost synchronously with the contralateral Si2 and was coactive with the efferent impulse activity in the contralateral body wall nerve. Perturbation of bursting in either Si3 or Si2 by current injection halted or phase-shifted the swim motor pattern, suggesting that they are both critical CPG members. Neither Si2 nor Si3 exhibited endogenous bursting properties when activated alone; activation of all four neurons was necessary to initiate and maintain the swim motor pattern. Si3 made a strong excitatory synapse onto the contralateral Si2 to which it is also electrically coupled. When Si3 was firing tonically but not exhibiting bursting, artificial enhancement of the Si3-to-Si2 synapse using dynamic clamp caused all four neurons to burst. In contrast, negation of the Si3-to-Si2 synapse by dynamic clamp blocked ongoing swim motor patterns. Together, these results suggest that the Dendronotus swim CPG is organized as a “twisted” half-center oscillator in which each “half” is composed of two excitatory-coupled neurons from both sides of the brain, each of which inhibits its contralateral counterpart. Consisting of only four neurons, this is perhaps the simplest known network oscillator for locomotion.

scholarly journals Feedforward discharges couple the singing central pattern generator and ventilation central pattern generator in the cricket abdominal central nervous system

2019 ◽  
Vol 205 (6) ◽  
pp. 881-895 ◽  
Author(s):  
Stefan Schöneich ◽  
Berthold Hedwig
Keyword(s):  
Motor Activity ◽  
Central Pattern Generator ◽  
Sensory Feedback ◽  
Motor Pattern ◽  
Pattern Generator ◽  
Abdominal Muscle ◽  
Excitatory Input ◽  
Intracellular Recordings ◽  
Motor Patterns ◽  
The Brain

Abstract We investigated the central nervous coordination between singing motor activity and abdominal ventilatory pumping in crickets. Fictive singing, with sensory feedback removed, was elicited by eserine-microinjection into the brain, and the motor activity underlying singing and abdominal ventilation was recorded with extracellular electrodes. During singing, expiratory abdominal muscle activity is tightly phase coupled to the chirping pattern. Occasional temporary desynchronization of the two motor patterns indicate discrete central pattern generator (CPG) networks that can operate independently. Intracellular recordings revealed a sub-threshold depolarization in phase with the ventilatory cycle in a singing-CPG interneuron, and in a ventilation-CPG interneuron an excitatory input in phase with each syllable of the chirps. Inhibitory synaptic inputs coupled to the syllables of the singing motor pattern were present in another ventilatory interneuron, which is not part of the ventilation-CPG. Our recordings suggest that the two centrally generated motor patterns are coordinated by reciprocal feedforward discharges from the singing-CPG to the ventilation-CPG and vice versa. Consequently, expiratory contraction of the abdomen usually occurs in phase with the chirps and ventilation accelerates during singing due to entrainment by the faster chirp cycle.

scholarly journals The Effect of Optogenetically Activating Glia on Neuronal Function

Neuroglia ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 57-67
Author(s):  
Cecilia Pankau ◽  
Shelby McCubbin ◽  
Robin L. Cooper
Keyword(s):  
Glial Cells ◽  
Motor Neurons ◽  
Body Wall ◽  
Motor Nerve ◽  
Neuronal Function ◽  
Electrical Insulator ◽  
Electrophysiological Recordings ◽  
Excitatory Junction Potentials ◽  
Body Wall Muscles ◽  
Vital Component

Glia, or glial cells, are considered a vital component of the nervous system, serving as an electrical insulator and a protective barrier from the interstitial (extracellular) media. Certain glial cells (i.e., astrocytes, microglia, and oligodendrocytes) within the CNS have been shown to directly affect neural functions, but these properties are challenging to study due to the difficulty involved with selectively-activating specific glia. To overcome this hurdle, we selectively expressed light-sensitive ion channels (i.e., channel rhodopsin, ChR2-XXL) in glia of larvae and adult Drosophila melanogaster. Upon activation of ChR2, both adults and larvae showed a rapid contracture of body wall muscles with the animal remaining in contracture even after the light was turned off. During ChR2-XXL activation, electrophysiological recordings of evoked excitatory junction potentials within body wall muscles of the larvae confirmed a train of motor nerve activity. Additionally, when segmental nerves were transected from the CNS and exposed to light, there were no noted differences in quantal or evoked responses. This suggests that there is not enough expression of ChR2-XXL to influence the segmental axons to detect in our paradigm. Activation of the glia within the CNS is sufficient to excite the motor neurons.

Swallow Pattern Generator Reconfiguration of the Respiratory Neural Network

2009 ◽  
Vol 18 (1) ◽  
pp. 3-12
Author(s):  
Andrea Vovka ◽  
Paul W. Davenport ◽  
Karen Wheeler-Hegland ◽  
Kendall F. Morris ◽  
Christine M. Sapienza ◽  
...  
Keyword(s):  
Behavioral Control ◽  
Upper Airway ◽  
Pattern Generator ◽  
Breathing Patterns ◽  
Motor Patterns ◽  
Control Assembly ◽  
Pharyngeal Swallow ◽  
Laryngeal Vestibule ◽  
Lower Airways ◽  
Swallow Apnea

Abstract When the nasal and oral passages converge and a bolus enters the pharynx, it is critical that breathing and swallow motor patterns become integrated to allow safe passage of the bolus through the pharynx. Breathing patterns must be reconfigured to inhibit inspiration, and upper airway muscle activity must be recruited and reconfigured to close the glottis and laryngeal vestibule, invert the epiglottis, and ultimately protect the lower airways. Failure to close and protect the glottal opening to the lower airways, or loss of the integration and coordination of swallow and breathing, increases the risk of penetration or aspiration. A neural swallow central pattern generator (CPG) controls the pharyngeal swallow phase and is located in the medulla. We propose that this swallow CPG is functionally organized in a holarchical behavioral control assembly (BCA) and is recruited with pharyngeal swallow. The swallow BCA holon reconfigures the respiratory CPG to produce the stereotypical swallow breathing pattern, consisting of swallow apnea during swallowing followed by prolongation of expiration following swallow. The timing of swallow apnea and the duration of expiration is a function of the presence of the bolus in the pharynx, size of the bolus, bolus consistency, breath cycle, ventilatory state and disease.

The Ligamentary System and the Segmental Musculature of Nephtys

1960 ◽  
Vol s3-101 (54) ◽  
pp. 149-176
Author(s):  
R. B. CLARK ◽  
M. E. CLARK
Keyword(s):  
Body Wall ◽  
The Body ◽  
Power Stroke ◽  
Coelomic Fluid ◽  
Unusual Structure ◽  
Shock Absorbers ◽  
Proximal Half ◽  
Unique System ◽  
Body Wall Muscles ◽  
The Impact

Nephtys lacks circular body-wall muscles. The chief antagonists of the longitudinal muscles are the dorso-ventral muscles of the intersegmental body-wall. The worm is restrained from widening when either set of muscles contracts by the combined influence of the ligaments, some of the extrinsic parapodial muscles, and possibly, to a limited extent, by the septal muscles. Although the septa are incomplete, they can and do form a barrier to the transmission of coelomic fluid from one segment to the next under certain conditions, particularly during eversion of the proboscis. Swimming is by undulatory movements of the body but the distal part of the parapodia execute a power-stroke produced chiefly by the contraction of the acicular muscles. It is suspected that the extrinsic parapodial muscles, all of which are inserted in the proximal half of the parapodium, serve to anchor the parapodial wall at the insertion of the acicular muscles and help to provide a rigid point of insertion for them. Burrowing is a cyclical process involving the violent eversion of the proboscis which makes a cavity in the sand. The worm is prevented from slipping backwards by the grip the widest segments have on the sides of the burrow. The proboscis is retracted and the worm crawls forward into the cavity it has made. The cycle is then repeated. Nephtys possesses a unique system of elastic ligaments of unusual structure. The anatomy of the system is described. The function of the ligaments appears to be to restrain the body-wall and parapodia from unnecessary and disadvantageous dilatations during changes of body-shape, and to serve as shock-absorbers against the high, transient, fluid pressures in the coelom, which are thought to accompany the impact of the proboscis against the sand when the worm is burrowing. From what is known of its habits, Nephtys is likely to undertake more burrowing than most other polychaetes.

scholarly journals Segmental differences in firing properties and potassium currents in Drosophila larval motoneurons

2012 ◽  
Vol 107 (5) ◽  
pp. 1356-1365 ◽  
Author(s):  
Subhashini Srinivasan ◽  
Kimberley Lance ◽  
Richard B. Levine
Keyword(s):  
Patch Clamp ◽  
Abdominal Segment ◽  
Body Wall ◽  
Potassium Currents ◽  
Whole Cell Patch Clamp ◽  
Voltage Dependent ◽  
Body Wall Muscles ◽  
Motoneuron Activity ◽  
Firing Properties ◽  
Thoracic And Abdominal

Potassium currents play key roles in regulating motoneuron activity, including functional specializations that are important for locomotion. The thoracic and abdominal segments in the Drosophila larval ganglion have repeated arrays of motoneurons that innervate body-wall muscles used for peristaltic movements during crawling. Although abdominal motoneurons and their muscle targets have been studied in detail, owing, in part, to their involvement in locomotion, little is known about the cellular properties of motoneurons in thoracic segments. The goal of this study was to compare firing properties among thoracic motoneurons and the potassium currents that influence them. Whole-cell, patch-clamp recordings performed from motoneurons in two thoracic and one abdominal segment revealed both transient and sustained voltage-activated K+ currents, each with Ca++-sensitive and Ca++-insensitive [A-type, voltage-dependent transient K+ current (IAv)] components. Segmental differences in the expression of voltage-activated K+ currents were observed. In addition, we demonstrate that Shal contributes to IAv currents in the motoneurons of the first thoracic segment.

Electrophysiology of Acanthocephalan Body Wall Muscles

1979 ◽  
Vol 82 (1) ◽  
pp. 273-280
Author(s):  
B. S. WONG ◽  
DONALD M. MILLER ◽  
T. T. DUNAGAN
Keyword(s):  
Light Microscopy ◽  
Intracellular Recording ◽  
Body Wall ◽  
Membrane Potentials ◽  
The Body ◽  
Spontaneous Potential ◽  
Body Wall Muscles ◽  
Macracanthorhynchus Hirudinaceus ◽  
Anterior Posterior

Body wall muscles of an acanthocephalan Macracanthorhynchus hirudinaceus were studied by means of scanning and light microscopy and intracellular recording of potentials. Three types of spontaneous potential changes were found: larger (L) potentials which usually exhibited overshoot and were as large as 65 mV; smaller symmetric (A) potentials approximately 15 mV in amplitude; and even smaller asymmetric (S) potentials which sometimes reached 10 mV. The potentials recorded depended upon the position of the electrode in the anterior-posterior, as well as the medialateral, axis. Tetrodotoxin eliminated L but not S potentials. Ouabain lengthened the time for depolarization of L potentials and depolarized the membrane potentials. It is suggested that the rete system activates the body wall muscles in Acanthocephala.

The gene tinman is required for specification of the heart and visceral muscles in Drosophila

Development ◽  
1993 ◽  
Vol 118 (3) ◽  
pp. 719-729 ◽  
Author(s):  
R. Bodmer
Keyword(s):  
Heart Development ◽  
Body Wall ◽  
Heart Cells ◽  
Visceral Muscle ◽  
Visceral Mesoderm ◽  
Body Wall Muscles ◽  
Visceral Muscles

The homeobox-containing gene tinman (msh-2, Bodmer et al., 1990 Development 110, 661–669) is expressed in the mesoderm primordium, and this expression requires the function of the mesoderm determinant twist. Later in development, as the first mesodermal subdivisions are occurring, expression becomes limited to the visceral mesoderm and the heart. Here, I show that the function of tinman is required for visceral muscle and heart development. Embryos that are mutant for the tinman gene lack the appearance of visceral mesoderm and of heart primordia, and the fusion of the anterior and posterior endoderm is impaired. Even though tinman mutant embryos do not have a heart or visceral muscles, many of the somatic body wall muscles appear to develop although abnormally. When the tinman cDNA is ubiquitously expressed in tinman mutant embryos, via a heatshock promoter, formation of heart cells and visceral mesoderm is partially restored, tinman seems to be one of the earliest genes required for heart development and the first gene reported for which a crucial function in the early mesodermal subdivisions has been implicated.

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