Role of intercostal muscles in the rib cage distortions produced by inspiratory loads

1982 ◽  
Vol 52 (3) ◽  
pp. 517-523 ◽  
Author(s):  
M. G. Sampson ◽  
A. De Troyer
Keyword(s):  
Electrical Activity ◽  
Strong Evidence ◽  
Normal Subjects ◽  
The Other ◽  
Reflex Activity ◽  
Quiet Breathing ◽  
Rib Cage ◽  
Intercostal Muscles ◽  
Inspiratory Activity

We studied the patterns of rib cage (RC) deformation in six normal subjects breathing against different resistive and elastic inspiratory loads, and we examined, with concentric needle electrodes, the role played by the inspiratory intercostal muscles in the development of these patterns. Four of the subjects deformed their RC to a more elliptical shape during loaded inspirations; RC anteroposterior diameter became smaller and RC lateral diameter became larger. The RC deformation increased as the load increased, but it appeared to be independent of the nature of the load. Moreover these deformations were associated with a marked increase in the inspiratory activity of the intercostals situated in the lateral parts of the RC and a striking diminution of the activity in the parasternal area. On the other hand, two subjects invariably breathed along their RC relaxation characteristic, and they showed an increased inspiratory activity in all regions of the intercostal musculature. These findings indicate that 1) the pattern of RC deformation during loaded inspirations is closely related to the activity and coordination of the various inspiratory intercostal muscles, and 2) the parasternal intercostals are not necessarily representative of all the inspiratory intercostals. They are also strong evidence against the concept that the parasternal intercostal electrical activity normally recorded during quiet breathing is an excitatory reflex activity.

Activation of the parasternal intercostals during breathing efforts in human subjects

1982 ◽  
Vol 52 (3) ◽  
pp. 524-529 ◽  
Author(s):  
A. De Troyer ◽  
M. G. Sampson
Keyword(s):  
Human Subjects ◽  
Normal Subjects ◽  
Emg Activity ◽  
Tidal Breathing ◽  
Quiet Breathing ◽  
Rib Cage ◽  
Intercostal Muscles ◽  
Breathing Maneuver ◽  
Inspiratory Activity

We have tested the possibility that the electromyographic (EMG) activity present in the parasternal intercostal muscles during quiet inspiration was reflexive, rather than agonistic, in nature. Using concentric needle electrodes we measured parasternal EMG activity in four normal subjects during various inspiratory maneuvers. We found that 1) phasic inspiratory activity was invariably present in the parasternal intercostals during quiet breathing, 2) the parasternal EMG activity was generally increased during attempts to perform the tidal breathing maneuver with the diaphragm alone, 3) parasternal EMG activity was markedly decreased or suppressed in the presence of rib cage distortion during diaphragmatic isovolume maneuvers, and 4) that EMG activity could not be voluntarily suppressed during breathing unless the inspired volume was trivial. We conclude that the parasternal EMG activity detected during quiet inspiration in the normal subjects depends on a central involuntary mechanism and is not related to activation of intercostal mechanoreceptors.

Inspiratory elevation of the ribs in the dog: primary role of the parasternals [published errata appear in J Appl Physiol 1991 Aug;71(2):following Table of Contents and 1991 Dec;71(6):following Author Index]

1991 ◽  
Vol 70 (4) ◽  
pp. 1447-1455 ◽  
Author(s):  
A. De Troyer
Keyword(s):  
Quantitative Analysis ◽  
Axial Displacement ◽  
The Other ◽  
Primary Role ◽  
Intercostal Muscles ◽  
The Third ◽  
Inspiratory Activity ◽  
Fourth Rib

To assess the relative contributions of the different groups of inspiratory intercostal muscles to the cranial motion of the ribs in the dog, we have measured the axial displacement of the fourth rib and recorded the electromyograms of the parasternal intercostal, external intercostal, and levator costae in the third interspace in 15 anesthetized animals breathing at rest. In eight animals, the parasternal intercostals were denervated in interspaces 1-5. This procedure caused a marked increase in the amount of external intercostal and levator costae inspiratory activity, and yet the inspiratory cranial motion of the rib was reduced by 55%. On the other hand, the external intercostals in interspaces 1-5 were sectioned in seven animals, and the reduction in the cranial rib motion was only 22%; the amount of parasternal and levator costae activity, however, was unchanged. When the parasternals in these animals were subsequently denervated, the levator costae inspiratory activity increased markedly, but the inspiratory cranial motion of the rib was abolished or reversed into an inspiratory caudal motion. These studies thus confirm that, in the dog breathing at rest, the parasternal intercostals have a larger role than the external intercostals and levator costae in causing the cranial motion of the ribs during inspiration. A quantitative analysis suggests that the parasternal contribution is approximately 80%.

Coordination between rib cage muscles and diaphragm during quiet breathing in humans

1984 ◽  
Vol 57 (3) ◽  
pp. 899-906 ◽  
Author(s):  
A. De Troyer ◽  
M. Estenne
Keyword(s):  
Tidal Volume ◽  
Marked Reduction ◽  
Emg Activity ◽  
Quiet Breathing ◽  
Rib Cage ◽  
Intercostal Muscles ◽  
Inspiratory Activity ◽  
Normal Humans ◽  
Volume Range

The pattern of activation of the scalenes and the parasternal intercostal muscles was studied in relation to the pattern of rib cage and abdominal motion during various respiratory maneuvers in the tidal volume range in five normal humans. Electromyograms (EMG) of the scalenes and parasternal intercostals were recorded with bipolar needle electrodes, and changes in abdominal and rib cage displacement were measured using linearized magnetometers. The scalenes and parasternal intercostals were always active during quiet breathing, and their pattern of activation was identical; in both muscles the EMG activity usually started together with the beginning of inspiration, increased in intensity as inspiration proceeded, and persisted into the early part of expiration. In addition, like the parasternal activity the scalene inspiratory activity persisted until the tidal volume was trivial, increased during tidal inspirations performed with the rib cage alone, and was nearly abolished during diaphragmatic isovolume maneuvers. However, attempts to perform tidal inspiration with the diaphragm alone, while causing an increase in parasternal EMG activity, were associated with a marked reduction or a suppression of scalene EMG activity and a reduced substantially distorted rib cage expansion. In particular, the upper rib cage was then moving paradoxically.(ABSTRACT TRUNCATED AT 250 WORDS)

Rôle du mésoderme somitique dans le développement de la cage thoracique de I'embryon d'oiseau. I. Origine du segment sternal et mécanismes de la différentiation des côtes

Development ◽  
1975 ◽  
Vol 33 (2) ◽  
pp. 291-311
Author(s):  
Alain Chevallier
Keyword(s):  
Chick Embryo ◽  
The Other ◽  
Pectoral Girdle ◽  
Thoracic Region ◽  
Rib Cage ◽  
Intercostal Muscles ◽  
Normal Limits ◽  
Somitic Mesoderm ◽  
Vertebral Segment

Role of the somitic mesoderm in the development of the rib cage of bird embryos. I. Origin of he sternal component and conditions for the development of the ribs The developmental origin of the sternal component of the ribs and the conditions for the development of the rib cage have been elucidated in bird embryos. Experiments consisted in homo- or heterospecific transplantations of 2-day-old quail or chick embryo somitic mesoderm into chick hosts of the same age in ortho- or heterotopic position along the cephalo-caudal axis. Results show that vertebral halves, ribs (not only their vertebral segment, but also their sternal component when they possess one), the trunk and intercostal muscles, as well as at least part of the scapula originate exclusively from the somitic material, while the sternum, ventral muscles and the other parts of the pectoral girdle are derived from the somatopleural mesoderm. The development of the rib basket is subjected to following rules: — only the somitic mesoderm of the prospective thoracic region (somites 19–26) is able togive rise to ribs. — only the somitic mesoderm of the posterior thoracic region (somites 22–26) is able to develop ribs with a sternal component. — the vertebral component of ribs can develop outside the thoracic region. — contrariwise, the sternal component can form only in the vicinity of the sternal anlage, i.e within about three somites in front and rear of the normal limits of the thoracic region. It is concluded that the somitic mesoderm is already regionalized at a stage slightly preceding its metamerization and that the somatopleural territory of the sternum plays a morphogenetic role in the development of the sternal component of ribs, although it does not make a cellular contribution to their construction.

BLOCKADE OF THE SURGE OF PROLACTIN AT PRO-OESTRUS BY ADMINISTRATION OF ANTI-OESTROGENIC SUBSTANCE, MER-25

1973 ◽  
Vol 74 (4) ◽  
pp. 769-774 ◽  
Author(s):  
Akira Yokoyama ◽  
Hiroshi Tomogane ◽  
Katuaki Ôta
Keyword(s):  
Strong Evidence ◽  
The Other ◽  
Other Hand

ABSTRACT A non-steroidal oestrogen antagonist, MER-25, was administered to cycling rats for elucidating the role of oestrogen in the surge of prolactin observed on the afternoon of pro-oestrus (POe). In animals injected with 20 mg of MER-25 intramuscularly on the afternoon (16.30 h) of the first day of dioestrus (D-1), the surge of prolactin was blocked while the level of prolactin on the afternoon of POe of these animals was significantly higher than that of the corresponding controls injected with oil. Ovulation was also blocked in these animals treated with the drug on the afternoon of D-l. On the other hand, treatment on the morning (10.30 h) of the 2nd day of dioestrus failed to prevent not only the surge of prolactin but also ovulation. These observations provide strong evidence for the view that oestrogen is responsible for the surge of prolactin on the afternoon of POe, and that the surge is accompanied by that of LH.

Abstract 4023: Aspirin “Resistance”: Role of Pre-existent Platelet Reactivity and Correlation Between Tests

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Andrew L Frelinger ◽  
Youfu Li ◽  
Matthew D Linden ◽  
Inge Tarnow ◽  
Marc R Barnard ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Platelet Function ◽  
Normal Subjects ◽  
Aspirin Resistance ◽  
The Other ◽  
List Type ◽  
Platelet Function Test ◽  
Function Test

Background: Aspirin “resistance” (i.e. hyporesponsiveness to aspirin in a platelet function test) has been widely reported, but the underlying mechanism is unclear. We examined the role of pre-existent platelet hyperreactivity in aspirin “resistance”. We also determined the correlation between aspirin resistance defined by serum thromboxane (TX) B 2 (the most specific test of aspirin’s effect) and other assays of platelet function. Methods: Platelet function measured before and after aspirin 81 mg daily for 7 days was analyzed by Spearman’s rank correlation. Normal subjects (n=165) were studied because virtually all clinically relevant patients are already taking aspirin. An additional advantage of the use of normal subjects is that the platelet response to stimuli is not influenced (with resultant increased scatter of the data) by an underlying disease, e.g. coronary artery disease, which causes platelet hyperreactivity. Results: The proportion of the post-aspirin platelet function predicted by the pre-aspirin platelet function was 28.3 ± 7.5% (mean ± asymptotic standard error) for serum TXB 2 , 39.3 ± 6.8% for urinary 11-dehydro TXB 2 , 4.4 ± 7.7% for arachidonic acid-induced platelet aggregation, 40.4 ± 7.1% for ADP-induced platelet aggregation, 26.3 ± 9.2% for the VerifyNow Aspirin Assay®, and 45.0 ± 10.9% for the TEG® PlateletMapping ™ System with arachidonic acid. Spearman rank order correlations were highly significant for comparisons between assays when both pre-aspirin and post-aspirin results were included in the analysis. However, residual serum TXB 2 levels post-aspirin treatment were not significantly associated with post-treatment results of any of the other assays. Platelet count correlated with pre-aspirin serum TXB 2 and VerifyNow Aspirin Assay, but not with any post-aspirin platelet function test. Conclusions: Aspirin “resistance” (i.e. hyporesponsiveness to aspirin in a laboratory test) is in part unrelated to aspirin but is the result of underlying platelet hyperreactivity prior to the institution of aspirin therapy. Individuals identified as aspirin “resistant” defined by serum TXB 2 are not the same individuals identified by the other tests.

The electrical activity of intercostal muscles during quiet breathing in rabbits

1968 ◽  
Vol 46 (5) ◽  
pp. 749-755
Author(s):  
William H. Boyd
Keyword(s):  
Electrical Activity ◽  
Progressive Increase ◽  
Quiet Breathing ◽  
Expiratory Phase ◽  
Intercostal Muscles ◽  
Continuous Activity

The electrical activity and the circumstances of contraction of the internal and external intercostal muscles were studied during quiet breathing in non-anesthetized rabbits resting in the sternal semirecumbent position. The activity was recorded via clip electrodes implanted in both muscles in a series of interspaces. The greater part of the expiratory phase was characterized by slight activity in both the internal and external intercostals, preceded and followed by brief periods of inactivity. Inspiration was accompanied by continuous activity in both sets of muscles until the last 20–40 ms of that phase. It was found that both internal and external intercostals were active during inspiration, that their activity was at its greatest during this phase, and that this activity was characterized by a progressive increase in external intercostal activity. There was no evidence of reciprocal innervation of intercostal muscles in this study.

Aristippus of Cyrene

2020 ◽  
pp. 380-411
Author(s):  
Voula Tsouna
Keyword(s):  
Strong Evidence ◽  
Crucial Role ◽  
Ethical Conduct ◽  
The Other ◽  
Philosophical Inquiry ◽  
Ethical Implications ◽  
Relative Value ◽  
The One ◽  
The City

“Aristippus of Cyrene” re-evaluates the evidence concerning, on the one hand, Aristippus’ alleged hedonism and, on the other, his affiliation with Socrates and the Socratic circle. The central thesis of the chapter is this: even though some sources attribute to Aristippus the sort of ethical hedonism that we know to have been held by his grandson (Aristippus the Younger), there is strong evidence that in fact Aristippus of Cyrene was not an ethical hedonist but endorsed Socratic concerns and values. These latter include philosophical inquiry focused on ethics, the paramount importance of philosophy for education and the care of one’s soul, concern to develop the virtues and assess the relative value of external goods, the crucial role of reason and prudence in ethical conduct, the ethical implications of systematically pursuing pleasure and avoiding pain, and the rationalism that should determine one’s attitudes toward relatives, acquaintances, fellow-citizens, and the city itself.

Respiratory-related activity of cricothyroid muscle in awake normal humans

1991 ◽  
Vol 70 (5) ◽  
pp. 2226-2232 ◽  
Author(s):  
J. R. Wheatley ◽  
A. Brancatisano ◽  
L. A. Engel
Keyword(s):  
Electrical Activity ◽  
Upper Airway ◽  
Peak Level ◽  
Cycle Duration ◽  
Quiet Breathing ◽  
Cricothyroid Muscle ◽  
Resistive Loading ◽  
Normal Humans ◽  
Integrated Emg

The role of the cricothyroid muscle (CT) in respiration is unclear. To examine the respiratory-related electrical activity of the CT, we measured its electromyogram (EMG) and compared it with that of the alae nasi (AN) in eight healthy subjects. During quiet breathing the CT EMG phasing was inspiratory in seven subjects. This pattern was similar to the AN with respect to phasing and shape of the integrated EMG. The onset of phasic CT and AN activity related to inspiration preceded flow by 173 +/- 39 and 570 +/- 76 (SE) ms, respectively (P less than 0.01). We measured the duration from onset of phasic activity to peak of the EMG (TA) and the total cycle duration (TT). TA/TT of the CT was 0.29 +/- 0.02, similar to that of the AN (0.28 +/- 0.03). Inspiratory resistive loading, panting, and voluntary hyperventilation increased CT activity above the peak level seen during tidal breathing. Voluntary glottic closure increased CT activity to a level above tonic but below peak tidal activity. The findings suggest that the phasic electrical activity of the CT simulates predominantly that of an upper airway dilator.

scholarly journals Modulation of the behavioral and electrical responses to the repellent DEET elicited by the pre-exposure to the same compound inBlattella germanica

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2150 ◽  
Author(s):  
Valeria Sfara ◽  
Gastón A. Mougabure-Cueto ◽  
Paola A. González-Audino
Keyword(s):  
Nitric Oxide ◽  
Electrical Activity ◽  
The Other ◽  
Nitric Oxide Donor ◽  
Chemical Stimulus ◽  
Sensory Adaptation ◽  
Transduction Pathway ◽  
Previous Exposure ◽  
Other Hand

Insects under different stimuli from the environment modify behavioural responses due to changes in the sensitivity of neurons at the peripheral and/or at the central level of the nervous system. This phenomenon is called neuronal plasticity, and sensory adaptation is an example of it. An insect repellent is a chemical that produces oriented movements of the insects away from its source. In this work we studied the modulation of the behavioural and electrical response to the repellent N, N-diethyl-3-methylbenzamide (DEET) in males of the German cockroachB. germanicaproduced by previous exposure to the same repellent.Methods.We determined repellency using a circular arena, one half of which was treated with DEET. The time spent by insects in each half of the arena was measured, and a repellency coefficient (RC) was calculated. The RCs of pre-exposed and non-pre-exposed insects were compared. To determine a possible role of nitric oxide in the modulation of the response to DEET after pre-exposure, the nitric oxide donor S-nitroso-acetyl-cysteine (SNAC) was applied on cockroaches’ antennae. The electrical activity of the cockroaches’ antennae in response to DEET was recorded using electroantennogram (EAG) technique. The response to DEET was recorded also after a long stimulation with the same repellent, and after topical application of SNAC and dbcGMP (a cGMP analogue) on the antennae.Results.We found that previous exposure ofB. germanicamales to the repellent DEET produced an increase of the repellency at the behavioural level, measured as RC. A possible role of nitric oxide (NO) in the transduction pathway of this phenomenon is suggested, since treatment of the cockroaches with the NO donor SNAC also produced an increase of the repellency elicited by DEET. On the other hand, the response of the cockroaches’ antennae exposed to DEET was determined electrophysiologically. The electrical activity in response to DEET decreased when the insects’ antennae were stimulated with a long pulse of the repellent. The activity of the antennae was restored after 10 min. Treatment of the antennae either with SNAC or dbGMPc also produced a decrease in the response of the antennae to the repellent.Discussion.The previous exposure to a chemical stimulus can modify the behaviour associated to the same stimulus, increasing or decreasing the behavioural response. In the case of DEET we found that pre-exposure increased DEET repellency in male cockroaches. We also found NO involvement in a similar phenomenon. On the other hand, the test showed that DEET is perceived by insects’ antennae as an odour. A long exposure of the antennae to DEET caused a transient decrease in the response of the antennae to the same compound. The same effect was achieved by treating the antennae with SNAC or dbcGMP, suggesting the involvement of the NO/cGMP system in the transduction pathway of the sensory adaptation phenomenon elicited by an odour in this species.

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