scholarly journals Role of Propriospinal Neurons in Control of Respiratory Muscles and Recovery of Breathing Following Injury

2020 ◽  
Vol 13 ◽  
Author(s):  
Victoria N. Jensen ◽  
Warren J. Alilain ◽  
Steven A. Crone
Keyword(s):  
Respiratory Muscles ◽  
Propriospinal Neurons

Respiratory response to partial paralysis in anesthetized dogs

1984 ◽  
Vol 56 (6) ◽  
pp. 1583-1588 ◽  
Author(s):  
A. Oliven ◽  
E. C. Deal ◽  
S. G. Kelsen ◽  
N. S. Cherniack
Keyword(s):  
Motor Activity ◽  
Respiratory Muscle ◽  
Respiratory Muscles ◽  
Peak Activity ◽  
Inspiratory Time ◽  
Muscle Paralysis ◽  
Anesthetized Dogs ◽  
Spontaneously Breathing ◽  
Partial Paralysis

The ability to maintain alveolar ventilation is compromised by respiratory muscle weakness. To examine the independent role of reflexly mediated neural mechanisms to decreases in the strength of contraction of respiratory muscles, we studied the effects of partial paralysis on the level and pattern of phrenic motor activity in 22 anesthetized spontaneously breathing dogs. Graded weakness induced with succinylcholine decreased tidal volume and prolonged both inspiratory and expiratory time causing hypoventilation and hypercapnia. Phrenic peak activity as well as the rate of rise of the integrated phrenic neurogram increased. However, when studied under isocapnic conditions, increases in the severity of paralysis, as assessed from the ratio of peak diaphragm electromyogram to peak phrenic activity, produced progressive increases in inspiratory time and phrenic peak activity but did not affect its rate of rise. After vagotomy, partial paralysis induced in 11 dogs with succinylcholine also prolonged the inspiratory burst of phrenic activity, indicating that vagal reflexes were not solely responsible for the alterations in respiratory timing. Muscle paresis was also induced with gallamine or dantrolene, causing similar responses of phrenic activity and respiratory timing. Thus, at constant levels of arterial CO2 in anesthetized dogs, respiratory muscle partial paralysis results in a decrease in breathing rate without changing the rate of rise of respiratory motor activity. This is not dependent solely on vagally mediated reflexes and occurs regardless of the pharmacological agent used. These observations in the anesthetized state are qualitatively different from the response to respiratory muscle paralysis or weakness observed in awake subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Relation between work output of respiratory muscles and end-tidal CO2 tension

1963 ◽  
Vol 18 (3) ◽  
pp. 497-504 ◽  
Author(s):  
J. Milic-Emili ◽  
J. M. Tyler
Keyword(s):  
Carbon Dioxide ◽  
Pulmonary Ventilation ◽  
Respiratory Muscles ◽  
Normal Subjects ◽  
Work Output ◽  
Inspiratory Muscles ◽  
Expiratory Muscles ◽  
End Tidal ◽  
End Tidal Co2

End-tidal CO2 tension, pulmonary ventilation, and work output of respiratory muscles were determined in six normal subjects breathing various mixtures of carbon dioxide in air, with three graded resistances added to both inspiration and expiration. In two individuals, the resistances were also added separately to inspiration or expiration. A linear relationship was found between work output of inspiratory muscles and end-tidal CO2 tension; this relationship was uninfluenced by added resistance. No consistent relationship was observed between either ventilation or work output of expiratory muscles and end-tidal CO2 tension. These results suggest that carbon dioxide controls directly the activity of inspiratory muscles alone and that the activity of expiratory muscles is only coincidentally involved. The possible role of intrinsic properties of respiratory muscles and of nervous mediation in the control of breathing is discussed. Submitted on October 22, 1962

Behavior of upper cervical inspiratory propriospinal neurons during fictive vomiting

1991 ◽  
Vol 65 (6) ◽  
pp. 1492-1500 ◽  
Author(s):  
S. Nonaka ◽  
A. D. Miller
Keyword(s):  
Firing Pattern ◽  
Impulse Activity ◽  
Abdominal Muscle ◽  
Lateral Funiculus ◽  
Upper Cervical ◽  
Spinal Segments ◽  
Propriospinal Neurons ◽  
Lumbar Cord ◽  
Stimulation Of

1. The role of upper cervical inspiratory (UCI)-modulated neurons in respiratory muscle control during vomiting was examined by recording the impulse activity of these neurons during fictive vomiting in decerebrate, paralyzed cats. Fictive vomiting was identified by a characteristic series of bursts of coactivation of phrenic and abdominal muscle nerves, elicited either by electrical stimulation of supradiaphragmatic vagal nerve afferents or by emetic drugs, which would be expected to produce expulsion of gastric contents in nonparalyzed animals. 2. Data were recorded from 43 propriospinal UCI neurons, located in the C1-C3 spinal segments near the border of the intermediate gray matter and lateral funiculus, which were antidromically activated with floating pin electrodes placed in the ipsilateral lateral funiculus, usually at T1-T3. Some cells (9/21 tested) were also activated from the upper lumbar cord (L1). During respiration, most neurons (n = 40) had an augmenting discharge pattern during inspiration. In addition, more than one-half (55%) fired tonically during the remainder of the respiratory cycle. About 40% of UCI neurons showed variations in their firing pattern during the noninspiratory portion of respiration. These latter two properties of UCI neurons were not observed in dorsal and ventral respiratory group (DRG and VRG-, respectively) bulbospinal inspiratory (I) neurons previously recorded under similar conditions. 3. During fictive vomiting, the firing pattern of most UCI neurons fell into one of three main categories. More than one-half (53%) were active in phase with bursts of phrenic discharge and were thus classified as Active-type cells.(ABSTRACT TRUNCATED AT 250 WORDS)

The Role of Respiratory Muscles in the Hyperinflation of Bronchial Asthma1–3

1980 ◽  
Vol 121 (3) ◽  
pp. 441-447 ◽  
Author(s):  
J. Martin ◽  
E. Powell ◽  
S. Shore ◽  
J. Emrich ◽  
L. A. Engel
Keyword(s):  
Respiratory Muscles

Ventilatory Mechanisms of the Amphibian, Xenopus Laevis; The Role of the Buccal Force Pump

1979 ◽  
Vol 80 (1) ◽  
pp. 251-269 ◽  
Author(s):  
S. S. BRETT ◽  
G. SHELTON
Keyword(s):  
Xenopus Laevis ◽  
Buccal Cavity ◽  
Respiratory Muscles ◽  
Lung Ventilation ◽  
Cavity Volume ◽  
Lung Volumes ◽  
Expired Air

1. Lung pressures, buccal pressures, lung volumes, and EMGs from respiratory muscles were measured in unrestrained Xenopus laevis to analyse their roles in the lung ventilation cycle. 2. Lung pressure was always maintained above atmospheric levels and a buccal pumping mechanism was used to fill the lungs in Xenopus, as in other Amphibia. 3. Xenopus, unlike other amphibians, does not ventilate the buccal cavity between lung ventilations. 4. Expiration of gases from the buccal cavity is aided by muscles which decrease buccal cavity volume. Other anurans increase buccal cavity volume during expiration. 5. The buccal phase of inspiration occurs after expired air has passed from the lung and buccal cavity, in comparison to the ranids and bufonids which inspire fresh air into the buccal cavity before expiration.

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