Diaphragm recovery by laryngeal innervation after bilateral phrenicotomy or complete C2 spinal section in rats

2006 ◽  
Vol 24 (1) ◽  
pp. 53-66 ◽  
Author(s):  
P. Gauthier ◽  
B. Baussart ◽  
J.C. Stamegna ◽  
M. Tadié ◽  
S. Vinit
Keyword(s):  
Spinal Section

Carotid chemoreceptors and vagi in hypoxic and cyanide-induced tachycardia in the dog

1981 ◽  
Vol 240 (6) ◽  
pp. H874-H880 ◽  
Author(s):  
P. D. Gupta ◽  
M. Singh
Keyword(s):  
Heart Rate ◽  
Carotid Sinus ◽  
Adrenergic Blockade ◽  
Vagus Nerves ◽  
Carotid Chemoreceptors ◽  
Control Heart ◽  
Systemic Hypoxia ◽  
Spinal Section ◽  
High Control ◽  
Control Heart Rate

We investigated the mechanisms underlying heart rate changes resulting from systemic hypoxia in anesthetized artificially ventilated dogs with low control heart rate (less than or equal to 93 beats/min). We observed that systemic hypoxia evoked tachycardia in intact dogs that was not significantly different from that evoked in dogs with beta-adrenergic blockade (BB). Also, tachycardia elicited in dogs with BB plus spinal section at C3 (BBSS) was significantly greater than in dogs with BBSS plus bilateral section of carotid sinus nerves. Furthermore, under various anesthetics, intracarotid injection of sodium cyanide induced a tachycardia response in dogs with low control heart rate (less than or equal to 97 beats/min) and a bradycardia response in dogs with high control heart rate (greater than or equal to 130 beats/min). These results suggest that 1) when the resting cardiac parasympathetic tone is high, systemic hypoxia evokes tachycardia which is mediated predominantly through efferent vagus nerves and 2) the stimulation of carotid chemoreceptors causes excitation of both cardioacceleratory and cardioinhibitory reflexes, the resultant response being dependent on the prevalent autonomic drive.

Phrenic afferent contribution to reflexes elicited by changes in diaphragm length

1990 ◽  
Vol 69 (2) ◽  
pp. 640-647 ◽  
Author(s):  
M. Cheeseman ◽  
W. R. Revelette
Keyword(s):  
Muscle Activation ◽  
Motor Drive ◽  
Inspiratory Time ◽  
Abdominal Compression ◽  
Dorsal Rhizotomy ◽  
Residual Capacity ◽  
Bilateral Vagotomy ◽  
Spinal Section ◽  
Length Changes ◽  
Crural Diaphragm

Recent evidence from several laboratories suggests that activation of afferents in the diaphragm can reflexly affect inspiratory muscle activation. This study determined whether afferents in the diaphragm contribute to compensatory changes in phrenic motor drive when the operating length of the diaphragm is suddenly increased. Experiments were performed in six closed-chest pentothal-anesthetized cats. Length changes were measured using a pair of piezoelectric crystals implanted in the left crural diaphragm. The crural electromyogram (EMGdi) was measured by electrodes fixed to each crystal. The animal was suspended in a spinal frame, and a Plexiglas tube was fitted around the cat's abdomen. A balloon placed inside the tube was inflated during the expiratory phase to produce a mean increase of 17% in diaphragm length at functional residual capacity. Ten trials were performed in succession under the following conditions: intact, after bilateral vagotomy, after spinal section at C7, and after cervical dorsal rhizotomy. Peak integrated EMGdi (integral of EMGdi) and neural inspiratory time (nTI) were measured for the last control inspiration and the first after inflation. There was a significant reduction in the peak integral of EMGdi when the length of the diaphragm was increased for all conditions except after rhizotomy. Although not measured, it is likely that the tension developed by the diaphragm was also increased during abdominal compression. Results suggest that afferents sensitive to changes in the operating length and/or tension in the diaphragm contribute to compensatory alterations in phrenic motor drive.

Role of vagal and spinal sensory pathways on eupneic diaphragmatic activity

1986 ◽  
Vol 60 (2) ◽  
pp. 479-485 ◽  
Author(s):  
Y. Jammes ◽  
M. J. Mathiot ◽  
S. Delpierre ◽  
C. Grimaud
Keyword(s):  
Spinal Reflexes ◽  
Vagal Afferents ◽  
Tracheal Occlusion ◽  
Sensory Pathways ◽  
Cervical Vagotomy ◽  
Experimental Protocols ◽  
Spinal Section ◽  
Spinal Afferents ◽  
Alpha Chloralose

The interactions between vagal and spinal afferents in the control of eupneic diaphragmatic activity were studied in two groups of cats anesthetized either with pentobarbital sodium (SPB) or with ethyl carbamate-alpha-chloralose (ECC), which enhanced spinal reflexes. Under both conditions of anesthesia two experimental protocols were performed: 1) bilateral cervical vagotomy followed by spinal section at C8 level or 2) spinal section followed by vagotomy. Changes in integrated diaphragmatic activity (Edi) were studied during eupneic ventilation and tracheal occlusion at end expiration. Vagotomy always significantly increased the amplitude of Edi during eupnea (SPB + 30%; ECC + 15%) and prolonged its duration (Tdi) (SPB + 110%; ECC + 75%) but did not modify the overall shape of the Edi vs. time relationship. Spinal section induced reverse changes in the amplitude of Edi, whether vagal afferents were present or suppressed and modified the shape of the Edi wave, but did not significantly modify Tdi. These results indicate that both vagal and spinal afferents may participate in the control of eupneic inspiration but exert different and interdependent influences on the recruitment and firing time of phrenic motoneurons. In addition, Tdi measured during tracheal occlusion (Todi) was markedly prolonged under ECC anesthesia. In this situation spinal section reduced Todi, which became close to the values obtained in intact or spinal cats under SPB anesthesia. Thus the response to tracheal occlusion at end expiration cannot be interpreted as resulting from the sole suppression of volume related vagal information.

scholarly journals Stimulus rhythm in reflex tetanic contraction

1923 ◽  
Vol 95 (666) ◽  
pp. 142-156 ◽  
Keyword(s):  
Stimulus Frequency ◽  
Spinal Reflexes ◽  
Primary Coil ◽  
Tetanic Contraction ◽  
Nerve Section ◽  
Hind Limbs ◽  
Different Types ◽  
Spinal Section ◽  
The Brain ◽  
Vibration Rate

When an afferent nerve is stimulated by single shocks following each other in not too fast succession the resulting reflex tetanus shows tensile vibrations corresponding with the rhythm of the stimulation. We find that the upper limit of stimulus frequency at which incompleteness of fusion of the component reflex contractions is still traceable differs considerably for different types of reflex. Method .—Our observations have been upon the mammalian preparation (cat) in the decerebrate condition. Transection of the brain-stem between the anterior and posterior colliculi was performed under complete chloroformanæsthesia, and the whole of the brain anterior to the transection removed. For purely spinal reflexes the level of the spinal cord transection lay variously between 12th thoracic and 3rd lumbar segments, the preparation being also decerebrate. In some instances the spinal section was performed, under full anæsthesia and asepsis, four to eight days prior to the decerebration. For use with the myograph the contracting muscle was in all cases isolatedly attached to it, and all other muscles in both hind limbs immobilized by appropriate nerve-section or resection. Fixation of the limb was obtained by steel drills in femur and tibia, a strong clamp holding the pelvis. For stimulation induction shocks were used, these being (except where otherwise stated) single shocks at frequencies varying from 35-95 per sec. For obtaining single-shock series of these frequencies a special key ( see Appendix) had been devised (C. S. S.) separating the make- and break-shocks of the ordinary inductorium, from which its spring interrupter had been removed. For most of the observations the primary coil was coreless, and the break-shock was given by short circuiting the primary coil, the current in the unshorted primary being usually 70 milliamps. The stimulating electrodes were 10 mm. apart with anode in all cases toward the cut end of the stimulated nerve. The isometric myograph was similar to that previously described. Its vibration rate when unattached to the muscle was over 1000 per sec.

Degenerative Lumbar Spine Stenosis Consensus Conference: the Italian job. Recommendations of the Spinal Section of the Italian Society of Neurosurgery

2021 ◽  
Vol 65 (2) ◽  
Author(s):  
Francesco COSTA ◽  
Gualtiero INNOCENZI ◽  
Franco GUIDA ◽  
Umberto AGRILLO ◽  
Giuseppe BARBAGALLO ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Consensus Conference ◽  
Italian Society ◽  
Degenerative Lumbar Spine ◽  
Spinal Section

NATURE OF PARESIS FOLLOWING LATERAL CORTICO-SPINAL SECTION IN MONKEYS

1943 ◽  
Vol 6 (5) ◽  
pp. 425-429 ◽  
Author(s):  
B. W. Cannon ◽  
L. E. Beaton ◽  
S. W. Ranson
Keyword(s):  
Spinal Section

Adaptive changes of locomotion after central and peripheral lesions

2004 ◽  
Vol 82 (8-9) ◽  
pp. 617-627 ◽  
Author(s):  
S Rossignol ◽  
E Brustein ◽  
L Bouyer ◽  
D Barthélemy ◽  
C Langlet ◽  
...  
Keyword(s):  
Peripheral Nerve ◽  
Locomotor Training ◽  
Control Mechanisms ◽  
Nerve Lesions ◽  
Adaptive Changes ◽  
Beneficial Effects ◽  
Spinal Lesions ◽  
Peripheral Nerve Lesions ◽  
Spinal Network ◽  
Spinal Section

This paper reviews findings on the adaptive changes of locomotion in cats after spinal cord or peripheral nerve lesions. From the results obtained after lesions of the ventral/ventrolateral pathways or the dorsal/dorsolateral pathways, we conclude that with extensive but partial spinal lesions, cats can regain voluntary quadrupedal locomotion on a treadmill. Although tract-specific deficits remain after such lesions, intact descending tracts can compensate for the lesioned tracts and access the spinal network to generate voluntary locomotion. Such neuroplasticity of locomotor control mechanisms is also demonstrated after peripheral nerve lesions in cats with intact or lesioned spinal cords. Some models have shown that recovery from such peripheral nerve lesions probably involves changes at the supra spinal and spinal levels. In the case of somesthesic denervation of the hindpaws, we demonstrated that cats with a complete spinal section need some cutaneous inputs to walk with a plantigrade locomotion, and that even in this spinal state, cats can adapt their locomotion to partial cutaneous denervation. Altogether, these results suggest that there is significant plasticity in spinal and supraspinal locomotor controls to justify the beneficial effects of early proactive and sustained locomotor training after central (Rossignol and Barbeau 1995; Barbeau et al. 1998) or peripheral lesions.Key words: spinal lesions, nerve lesions, locomotion, neuroplisticity, locomotor training.

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