Crossed reflex responses to flexor nerve stimulation in mice

2022 ◽  
Author(s):  
Olivier D. Laflamme ◽  
Marwan Ibrahim ◽  
Turgay Akay
Keyword(s):  
Peroneal Nerve ◽  
Muscle Activation ◽  
Mouse Genetics ◽  
Motor Responses ◽  
Reflex Pathway ◽  
Reflex Responses ◽  
Spinal Circuitry ◽  
Extensor Muscles ◽  
Stimulation Of

Motor responses in one leg to sensory stimulation of the contralateral leg have been named "crossed reflexes" and extensively investigated in cats and humans. Despite this effort, a circuit-level understanding of the crossed reflexes has remained missing. In mice, advances in molecular genetics enabled insights into the "commissural spinal circuitry" that ensures coordinated leg movements during locomotion. Despite some common features between the commissural spinal circuitry and the circuit for the crossed reflexes, the degree to which they overlap has remained obscure. Here, we describe excitatory crossed reflex responses elicited by electrically stimulating the common peroneal nerve that mainly innervate ankle flexor muscles and the skin on antero-lateral aspect of the hind leg. Stimulation of the peroneal nerve with low current intensity evoked low amplitude motor responses in the contralateral flexor and extensor muscles. At higher current strengths, stimulation of the same nerve evoked stronger and more synchronous responses in the same contralateral muscles. In addition to the excitatory crossed reflex pathway indicated by muscle activation, we demonstrate the presence of an inhibitory crossed reflex pathway, which was modulated when the motor pools were active during walking. The results are compared with the crossed reflex responses initiated by stimulating proprioceptors from extensor muscles and cutaneous afferents from the posterior part of the leg. We anticipate that these findings will be essential for future research combining the in vivo experiments presented here with mouse genetics to understand crossed reflex pathways at the network level in vivo.

scholarly journals In vivo Photonic Stimulation of Sciatic Nerve with a 1470 nm Laser

2016 ◽  
Vol 26 (3) ◽  
Author(s):  
Marie Dautrebande ◽  
Pascal Doguet ◽  
Simon-Pierre Gorza ◽  
Jean Delbeke ◽  
Yohan Botquin ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Sciatic Nerve ◽  
Nerve Stimulation ◽  
Muscle Activation ◽  
Radiant Exposure ◽  
Stimulation Of

Photonic stimulation is a new modality of nerve stimulation, which could overcome some of the electrical stimulation limitations. In this paper, we present the results of photonic stimulation of rodent sciatic nerve with a 1470 nm laser. Muscle activation was observed with radiant exposure of 0.084 J/cm<sup>2</sup>.

scholarly journals Physiological recruitment of motor units by high-frequency electrical stimulation of afferent pathways

2015 ◽  
Vol 118 (3) ◽  
pp. 365-376 ◽  
Author(s):  
Jakob L. Dideriksen ◽  
Silvia Muceli ◽  
Strahinja Dosen ◽  
Christopher M. Laine ◽  
Dario Farina
Keyword(s):  
Electrical Stimulation ◽  
Motor Unit ◽  
High Frequency ◽  
Muscle Activation ◽  
Motor Units ◽  
H Reflex ◽  
Motor Unit Recruitment ◽  
Afferent Stimulation ◽  
Reflex Responses ◽  
Stimulation Of

Neuromuscular electrical stimulation (NMES) is commonly used in rehabilitation, but electrically evoked muscle activation is in several ways different from voluntary muscle contractions. These differences lead to challenges in the use of NMES for restoring muscle function. We investigated the use of low-current, high-frequency nerve stimulation to activate the muscle via the spinal motoneuron (MN) pool to achieve more natural activation patterns. Using a novel stimulation protocol, the H-reflex responses to individual stimuli in a train of stimulation pulses at 100 Hz were reliably estimated with surface EMG during low-level contractions. Furthermore, single motor unit recruitment by afferent stimulation was analyzed with intramuscular EMG. The results showed that substantially elevated H-reflex responses were obtained during 100-Hz stimulation with respect to a lower stimulation frequency. Furthermore, motor unit recruitment using 100-Hz stimulation was not fully synchronized, as it occurs in classic NMES, and the discharge rates differed among motor units because each unit was activated only after a specific number of stimuli. The most likely mechanism behind these observations is the temporal summation of subthreshold excitatory postsynaptic potentials from Ia fibers to the MNs. These findings and their interpretation were also verified by a realistic simulation model of afferent stimulation of a MN population. These results suggest that the proposed stimulation strategy may allow generation of considerable levels of muscle activation by motor unit recruitment that resembles the physiological conditions.

scholarly journals Titin switches from an extensible spring to a mechanical rectifier upon muscle activation

2021 ◽  
Author(s):  
Caterina Squarci ◽  
Pasquale Bianco ◽  
Massimo Reconditi ◽  
Marco Caremani ◽  
Theyencheri Narayanan ◽  
...  
Keyword(s):  
Thin Filament ◽  
Muscle Activation ◽  
Striated Muscle ◽  
Thick Filament ◽  
Frog Muscle ◽  
Motor Responses ◽  
Filament Activation ◽  
Single Fibres ◽  
Myosin Motors ◽  
Stimulation Of

In contracting striated muscle titin acts as a spring in parallel with the array of myosin motors in each half-sarcomere and could prevent the intrinsic instability of thousands of serially linked half-sarcomeres, if its stiffness, at physiological sarcomere lengths (SL), were ten times larger than reported. Here we define titin mechanical properties during tetanic stimulation of single fibres of frog muscle by suppressing myosin motor responses with Para-Nitro-Blebbistatin, which is able to freeze thick filament in the resting state. We discover that thin filament activation switches I-band titin spring from the large SL-dependent extensibility of the OFF-state to an ON-state in which titin acts as a SL-independent mechanical rectifier, allowing free shortening while opposing stretch with an effective stiffness 4 pN nm-1 per half-thick filament. In this way during contraction titin limits weak half-sarcomere elongation to a few % and, also, provides an efficient link for mechanosensing-based thick filament activation.

scholarly journals Selective stimulation of IL-4 receptor on smooth muscle induces airway hyperresponsiveness in mice

2011 ◽  
Vol 208 (4) ◽  
pp. 853-867 ◽  
Author(s):  
Charles Perkins ◽  
Noriko Yanase ◽  
George Smulian ◽  
Lucy Gildea ◽  
Tatyana Orekov ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Airway Hyperresponsiveness ◽  
Muscle Activation ◽  
Cell Type ◽  
Cellular Mechanisms ◽  
Bronchial Smooth Muscle ◽  
Airway Anatomy ◽  
The Common ◽  
Stimulation Of

Production of the cytokines IL-4 and IL-13 is increased in both human asthma and mouse asthma models, and Stat6 activation by the common IL-4/IL-13R drives most mouse model pathophysiology, including airway hyperresponsiveness (AHR). However, the precise cellular mechanisms through which IL-4Rα induces AHR remain unclear. Overzealous bronchial smooth muscle constriction is thought to underlie AHR in human asthma, but the smooth muscle contribution to AHR has never been directly assessed. Furthermore, differences in mouse versus human airway anatomy and observations that selective IL-13 stimulation of Stat6 in airway epithelium induces murine AHR raise questions about the importance of direct IL-4R effects on smooth muscle in murine asthma models and the relevance of these models to human asthma. Using transgenic mice in which smooth muscle is the only cell type that expresses or fails to express IL-4Rα, we demonstrate that direct smooth muscle activation by IL-4, IL-13, or allergen is sufficient but not necessary to induce AHR. Five genes known to promote smooth muscle migration, proliferation, and contractility are activated by IL-13 in smooth muscle in vivo. These observations demonstrate that IL-4Rα promotes AHR through multiple mechanisms and provide a model for testing smooth muscle–directed asthma therapeutics.

scholarly journals Optogenetic surface stimulation of the rat cervical spinal cord

2018 ◽  
Vol 120 (2) ◽  
pp. 795-811 ◽  
Author(s):  
S. E. Mondello ◽  
M. D. Sunshine ◽  
A. E. Fischedick ◽  
S. J. Dreyer ◽  
G. D. Horwitz ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Muscle Activation ◽  
Cervical Spinal Cord ◽  
Dorsal Surface ◽  
Rat Spinal Cord ◽  
Intraspinal Microstimulation ◽  
Spinal Circuitry ◽  
Cord Injury ◽  
Specific Alternative ◽  
Stimulation Of

Electrical intraspinal microstimulation (ISMS) at various sites along the cervical spinal cord permits forelimb muscle activation, elicits complex limb movements and may enhance functional recovery after spinal cord injury. Here, we explore optogenetic spinal stimulation (OSS) as a less invasive and cell type-specific alternative to ISMS. To map forelimb muscle activation by OSS in rats, adeno-associated viruses (AAV) carrying the blue-light sensitive ion channels channelrhodopsin-2 (ChR2) and Chronos were injected into the cervical spinal cord at different depths and volumes. Following an AAV incubation period of several weeks, OSS-induced forelimb muscle activation and movements were assessed at 16 sites along the dorsal surface of the cervical spinal cord. Three distinct movement types were observed. We find that AAV injection volume and depth can be titrated to achieve OSS-based activation of several movements. Optical stimulation of the spinal cord is thus a promising method for dissecting the function of spinal circuitry and targeting therapies following injury. NEW & NOTEWORTHY Optogenetics in the spinal cord can be used both for therapeutic treatments and to uncover basic mechanisms of spinal cord physiology. For the first time, we describe the methodology and outcomes of optogenetic surface stimulation of the rat spinal cord. Specifically, we describe the evoked responses of forelimbs and address the effects of different adeno-associated virus injection paradigms. Additionally, we are the first to report on the limitations of light penetration through the rat spinal cord.

Stimulation of ovarian progesterone secretion by oxytocin in vivo

1988 ◽  
Vol 117 (4_Suppl) ◽  
pp. S199-S200
Author(s):  
E. DIETRICH ◽  
K. RENTELMANN ◽  
W. WUTTKE
Keyword(s):  
Progesterone Secretion ◽  
Stimulation Of

Reflex responses evoked from cats' coccygeal ventral roots by electrical stimulation of the tail nerves

1987 ◽  
Vol 96 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Margarita Martinez-Gomez ◽  
Pablo Pacheco ◽  
Bernardo Dubrovsky
Keyword(s):  
Electrical Stimulation ◽  
Reflex Responses ◽  
Ventral Roots ◽  
Stimulation Of

scholarly journals GPR40 Is Necessary but Not Sufficient for Fatty Acid Stimulation of Insulin Secretion In Vivo

Diabetes ◽  
2007 ◽  
Vol 56 (4) ◽  
pp. 1087-1094 ◽  
Author(s):  
M. G. Latour ◽  
T. Alquier ◽  
E. Oseid ◽  
C. Tremblay ◽  
T. L. Jetton ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Fatty Acid ◽  
Insulin Secretion In Vivo ◽  
Stimulation Of

Thrombopoietin-Induced Stimulation of Megakaryocyte- Enriched Bone Marrow Cultures

1979 ◽  
Author(s):  
K. L. Kellar ◽  
B. L. Evatt ◽  
C. R. McGrath ◽  
R. B. Ramsey
Keyword(s):  
Bone Marrow ◽  
Dna Synthesis ◽  
Bone Marrow Cells ◽  
Rabbit Plasma ◽  
Bone Marrow Cultures ◽  
Plasma Fractions ◽  
Marrow Cultures ◽  
Stimulation Of

Liquid cultures of bone marrow cells enriched for megakaryocytes were assayed for incorporation of 3H-thymidine (3H-TdR) into acid-precipitable cell digests to determine the effect of thrombopoietin on DNA synthesis. As previously described, thrombopoietin was prepared by ammonium sulfate fractionation of pooled plasma obtained from thrombocytopenic rabbits. A control fraction was prepared from normal rabbit plasma. The thrombopoietic activity of these fractions was determined in vivo with normal rabbits as assay animals and the rate of incorporation of 75Se-selenomethionine into newly formed platelets as an index of thrombopoietic activity of the infused material. Guinea pig megakaryocytes were purified using bovine serum albumin gradients. Bone marrow cultures containing 1.5-3.0x104 cells and 31%-71% megakaryocytes were incubated 18 h in modified Dulbecco’s MEM containing 10% of the concentrated plasma fractions from either thrombocytopenic or normal rabbits. In other control cultures, 0.9% NaCl was substituted for the plasma fractions. 3H-TdR incorporation was measured after cells were incubated for 3 h with 1 μCi/ml. The protein fraction containing thrombopoietin-stimulating activity caused a 25%-31% increase in 3H-TdR incorporation over that in cultures which were incubated with the similar fraction from normal plasma and a 29% increase over the activity in control cultures to which 0.9% NaCl had been added. These data suggest that thrombopoietin stimulates DNA synthesis in megakaryocytes and that this tecnique may be useful in assaying thrombopoietin in vitro.

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