scholarly journals Phrenic motoneuron structural plasticity across models of diaphragm muscle paralysis

2018 ◽  
Vol 526 (18) ◽  
pp. 2973-2983 ◽  
Author(s):  
Carlos B. Mantilla ◽  
Wen-Zhi Zhan ◽  
Heather M. Gransee ◽  
Y. S. Prakash ◽  
Gary C. Sieck
Keyword(s):  
Structural Plasticity ◽  
Diaphragm Muscle ◽  
Muscle Paralysis ◽  
Phrenic Motoneuron

scholarly journals Key aspects of phrenic motoneuron and diaphragm muscle development during the perinatal period

2008 ◽  
Vol 104 (6) ◽  
pp. 1818-1827 ◽  
Author(s):  
Carlos B. Mantilla ◽  
Gary C. Sieck
Keyword(s):  
Muscle Development ◽  
Respiratory Muscles ◽  
Motor Units ◽  
Perinatal Period ◽  
Diaphragm Muscle ◽  
Postnatal Maturation ◽  
Motor Behaviors ◽  
Phrenic Motoneurons ◽  
Phrenic Motoneuron ◽  
Key Aspects

At the time of birth, respiratory muscles must be activated to sustain ventilation. The perinatal development of respiratory motor units (comprising an individual motoneuron and the muscle fibers it innervates) shows remarkable features that enable mammals to transition from in utero conditions to the air environment in which the remainder of their life will occur. In addition, significant postnatal maturation is necessary to provide for the range of motor behaviors necessary during breathing, swallowing, and speech. As the main inspiratory muscle, the diaphragm muscle (and the phrenic motoneurons that innervate it) plays a key role in accomplishing these behaviors. Considerable diversity exists across diaphragm motor units, but the determinant factors for this diversity are unknown. In recent years, the mechanisms underlying the development of respiratory motor units have received great attention, and this knowledge may provide the opportunity to design appropriate interventions for the treatment of respiratory disease not only in the perinatal period but likely also in the adult.

Contractile and fatigue properties of the rat diaphragm musculature during the perinatal period

2000 ◽  
Vol 88 (2) ◽  
pp. 573-580 ◽  
Author(s):  
Miguel Martin-Caraballo ◽  
Paul A. Campagnaro ◽  
Yuan Gao ◽  
John J. Greer
Keyword(s):  
Full Range ◽  
Relaxation Times ◽  
Diaphragm Muscle ◽  
Fatigue Properties ◽  
Repetitive Firing ◽  
Force Frequency ◽  
Muscle Properties ◽  
Tetanic Force ◽  
Phrenic Motoneuron

The following two hypotheses regarding diaphragm contractile properties in the perinatal rat were tested. First, there is a major transformation of contractile and fatigue properties during the period between the inception of inspiratory drive transmission in utero and birth. Second, the diaphragm muscle properties develop to functionally match changes occurring in phrenic motoneuron electrophysiological properties. Muscle force recordings and intracellular recordings of end-plate potentials were measured by using phrenic nerve-diaphragm muscle in vitro preparations isolated from rats on embryonic day 18 and postnatal days 0–1. The following age-dependent changes occurred: 1) twitch contraction and half relaxation times decreased approximately two- and threefold, respectively; 2) the tetanic force levels increased approximately fivefold; 3) the ratio of peak twitch force to maximum tetanic force decreased 2.3-fold; 4) the range of forces generated by the diaphragm in response to graded nerve stimulation increased approximately twofold; 5) the force-frequency curve was shifted to the right; and 6) the propensity for neuromuscular transmission failure decreased. In conclusion, the diaphragm contractile and phrenic motoneuron repetitive firing properties develop in concert so that the full range of potential diaphragm force recruitment can be utilized and problems associated with diaphragm fatigue are minimized.

Phrenic motoneuron morphology during rapid diaphragm muscle growth

2000 ◽  
Vol 89 (2) ◽  
pp. 563-572 ◽  
Author(s):  
Y. S. Prakash ◽  
Carlos B. Mantilla ◽  
Wen-Zhi Zhan ◽  
Kenneth G. Smithson ◽  
Gary C. Sieck
Keyword(s):  
Surface Area ◽  
Muscle Growth ◽  
Diaphragm Muscle ◽  
Type I ◽  
Cross Sectional ◽  
Early Postnatal Development ◽  
Adult Rat ◽  
Surface Areas ◽  
Phrenic Motoneurons ◽  
Phrenic Motoneuron

In the adult rat, there is a general correspondence between the sizes of motoneurons, motor units, and muscle fibers that has particular functional importance in motor control. During early postnatal development, after the establishment of singular innervation, there is rapid growth of diaphragm muscle (Diam) fibers. In the present study, the association between Diamfiber growth and changes in phrenic motoneuron size (both somal and dendritic) was evaluated from postnatal day 21 (D21) to adulthood. Phrenic motoneurons were retrogradely labeled with fluorescent tetramethylrhodamine dextran (3,000 MW), and motoneuron somal volumes and surface areas were measured using three-dimensional confocal microscopy. In separate animals, phrenic motoneurons retrogradely labeled with choleratoxin B-fragment were visualized using immunocytochemistry, and dendritic arborization was analyzed by camera lucida. Between D21 and adulthood, Diam fiber cross-sectional area increased by ∼164% overall, with the growth of type II fibers being disproportionate to that of type I fibers. There was also substantial growth of phrenic motoneurons (∼360% increase in total surface area), during this same period, that was primarily attributable to an expansion of dendritic surface area. Comparison of the distribution of phrenic motoneuron surface areas between D21 and adults suggests the establishment of a bimodal distribution that may have functional significance for motor unit recruitment in the adult rat.

scholarly journals Unilateral diaphragm muscle paralysis minimally impacts ventilation in rodents (871.5)

2014 ◽  
Vol 28 (S1) ◽  
Author(s):  
Gary Sieck ◽  
Heather Gransee ◽  
Luther Gill ◽  
Amy Jorgenson ◽  
Juan Medina ◽  
...  
Keyword(s):  
Diaphragm Muscle ◽  
Muscle Paralysis

scholarly journals Impact of glutamatergic and serotonergic neurotransmission on diaphragm muscle activity after cervical spinal hemisection

2017 ◽  
Vol 118 (3) ◽  
pp. 1732-1738 ◽  
Author(s):  
Carlos B. Mantilla ◽  
Heather M. Gransee ◽  
Wen-Zhi Zhan ◽  
Gary C. Sieck
Keyword(s):  
Spinal Cord ◽  
Nmda Receptor ◽  
Muscle Activity ◽  
Spontaneous Recovery ◽  
Cervical Spinal Cord ◽  
Diaphragm Muscle ◽  
Emg Activity ◽  
Emg Amplitude ◽  
Cord Injury ◽  
Phrenic Motoneuron

Incomplete cervical spinal cord hemisection at C2 (SH) disrupts descending excitatory drive to phrenic motoneurons, paralyzing the ipsilateral diaphragm muscle. Spontaneous recovery over time is associated with increased phrenic motoneuron expression of glutamatergic N-methyl-d-aspartate (NMDA) and serotonergic 5-HT2A receptors. We hypothesized that NMDA and 5-HT2A receptor-mediated neurotransmission play a role in ipsilateral diaphragm muscle activity post-SH. Adult male Sprague-Dawley rats were implanted with bilateral diaphragm EMG electrodes for chronic EMG recordings up to 28 days post-SH (SH 28D). The extent of recovery was calculated by peak root-mean-square (RMS) EMG amplitude. In all animals, absence of ipsilateral activity was verified at 3 days post-SH. Diaphragm EMG activity was also recorded during exposure to hypoxia-hypercapnia (10% O2-5% CO2). In SH animals displaying recovery of ipsilateral diaphragm EMG activity at SH 28D, cervical spinal cord segments containing the phrenic motor nucleus (C3–C5) were surgically exposed and either the NMDA receptor antagonist d-2-amino-5-phosphonovalerate (d-AP5; 100 mM, 30 μl) or 5-HT2A receptor antagonist ketanserin (40 mM, 30 μl) was instilled intrathecally. Following d-AP5, diaphragm EMG amplitude was reduced ipsilaterally, during both eupnea (42% of pre-d-AP5 value; P = 0.007) and hypoxia-hypercapnia (31% of pre-d-AP5 value; P = 0.015), with no effect on contralateral EMG activity or in uninjured controls. Treatment with ketanserin did not change ipsilateral or contralateral RMS EMG amplitude in SH animals displaying recovery at SH 28D. Our results suggest that spinal glutamatergic NMDA receptor-mediated neurotransmission plays an important role in ipsilateral diaphragm muscle activity after cervical spinal cord injury. NEW & NOTEWORTHY Spontaneous recovery following C2 spinal hemisection (SH) is associated with increased phrenic motoneuron expression of glutamatergic and serotonergic receptors. In this study, we show that pharmacological inhibition of glutamatergic N-methyl-d-aspartate (NMDA) receptors blunts ipsilateral diaphragm activity post-SH. In contrast, pharmacological inhibition of serotonergic 5-HT2A receptors does not change diaphragm EMG activity post-SH. Our results suggest that NMDA receptor-mediated glutamatergic neurotransmission plays an important role in enhancing rhythmic respiratory-related diaphragm activity after spinal cord injury.

Cryo-electron microscopy of two-dimensional crystals of reduced type B botulinum neurotoxin

1992 ◽  
Vol 50 (1) ◽  
pp. 530-531
Author(s):  
P. F. Flicker ◽  
V.S. Kulkarni ◽  
J. P. Robinson ◽  
G. Stubbs ◽  
B. R. DasGupta
Keyword(s):  
Disulfide Bonds ◽  
Clostridium Botulinum ◽  
Structural Changes ◽  
Two Dimensional ◽  
Type B ◽  
Single Chain ◽  
Muscle Paralysis ◽  
Cryo Electron Microscopy ◽  
Disulfide Linkages ◽  
Intracellular Action

Botulinum toxin is a potent neurotoxin produced by Clostridium botulinum. The toxin inhibits release of neurotransmitter, causing muscle paralysis. There are several serotypes, A to G, all of molecular weight about 150,000. The protein exists as a single chain or or as two chains, with two disulfide linkages. In a recent investigation on intracellular action of neurotoxins it was reported that type B neurotoxin can inhibit the release of Ca++-activated [3H] norepinephrine only if the disulfide bonds are reduced. In order to investigate possible structural changes in the toxin upon reduction of the disulfide bonds, we have prepared two-dimensional crystals of reduced type B neurotoxin. These two-dimensional crystals will be compared with those of the native (unreduced) type B toxin.

Role of structural plasticity in the human brain for multisensory compensation following unilateral peripheral vestibular lesion

2008 ◽  
Vol 35 (S 01) ◽  
Author(s):  
C Helmchen ◽  
J Klinkenstein ◽  
T Sander ◽  
J Gliemroth ◽  
B Machner ◽  
...  
Keyword(s):  
Human Brain ◽  
Structural Plasticity ◽  
Vestibular Lesion

TBE in Lithuania

2020 ◽  
Keyword(s):  
Viral Encephalitis ◽  
Clinical Symptoms ◽  
Shoulder Girdle ◽  
Muscle Paralysis ◽  
First Case ◽  
Tick Borne Encephalitis ◽  
Autopsy Data ◽  
Forest Worker ◽  
Girdle Muscle ◽  
Shoulder Girdle Muscle

The first case of tick-borne encephalitis (TBE) in Lithuania, diagnosed by clinical and epidemiologic criteria only, was reported in 1953. A forest worker became ill with the disease in April after a tick bite, had a typical clinical presentation with shoulder girdle muscle paralysis and bulbar syndrome, and died after 12 days from the start of clinical symptoms. Autopsy data were compatible with viral encephalitis.1 Serological diagnosis of TBE in Lithuania was started in 1970.2

Structural Plasticity of the Proteasome and Its Function in Antigen Processing

2001 ◽  
Vol 21 (4) ◽  
pp. 21 ◽  
Author(s):  
Marcus Groettrup ◽  
Maries van den Broek ◽  
Katrin Schwarz ◽  
Annalisa Macagno ◽  
Selina Khan ◽  
...  
Keyword(s):  
Antigen Processing ◽  
Structural Plasticity
Sign in / Sign up

Export Citation Format

Share Document