STUDIES ON THE RESPIRATORY MECHANISM IN SKATES

1931 ◽  
Vol 6 (1) ◽  
pp. 315-339 ◽  
Author(s):  
B. P. BABKIN ◽  
R. H. M'GONIGLE
Keyword(s):  
Central Nervous System ◽  
Experimental Investigation ◽  
Water Flow ◽  
Sea Water ◽  
Circulatory Arrest ◽  
Respiratory Control ◽  
Reflex Mechanism ◽  
Branchial Arches ◽  
The Central Nervous System ◽  
Respiratory Mechanism

Spinal skates (Raja spp.), or specimens under Dial, Ciba (0.4 cc. per kg.), were employed. When such means of circulatory arrest were used as exsanguination, ligation of the conus arteriosus, and large doses of pilocarpin (8 mg. per kg.), respiration continued for about forty-two minutes after the blood-flow had ceased. Experimental investigation of the effect of water-flow indicated it to be a primary factor in respiratory regulation as the movements disappeared when water-flow was stopped (they were diminished very much by too great water-flow). Special movements, "gasping", would then appear. Normal rhythm returned as soon as water-flow was resumed. This picture was profoundly altered by perfusion of cocaine solution (0.25% in sea-water) through the mouth and gills. If the water-flow be stopped for a longer period, in about five minutes would appear regular, though infrequent, and often weaker contractions of the branchial arches. The period of time during which these contractions would continue would depend upon the state of excitability of the respiratory centres. Certain experiments carried out on the central nervous system tend to confirm the idea of a segmental arrangement of the respiratory centres. A double mechanism for respiratory control is indicated; a weakly developed automaticity of the centres, and a finely elaborated reflex mechanism, the reaction of which varies with the stimuli received.

Clinical neurologic and developmental studies after cardiac surgery utilizing hypothermic circulatory arrest and cardiopulmonary bypass

1993 ◽  
Vol 3 (3) ◽  
pp. 308-316 ◽  
Author(s):  
Gil Wernovsky ◽  
Richard A. Jonas ◽  
Paul R. Hickey ◽  
Adré J. du Plessis ◽  
Jane W. Newburger
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Cardiac Surgery ◽  
Cardiopulmonary Bypass ◽  
Circulatory Arrest ◽  
Neurodevelopmental Outcome ◽  
Hypothermic Circulatory Arrest ◽  
Cerebral Injury ◽  
Profound Hypothermia ◽  
The Central Nervous System

The dramatic reduction in surgical mortality associated with repair of congenital heart anomalies in recent decades has been accompanied by a growing recognition of adverse neurologic sequels in some of the survivors. Abnormalities of the central nervous system may be a function of coexisting cerebral abnormalities or acquired events unrelated to surgical management (such as paradoxical embolus, cerebral infection, or effects of chronic cyanosis), but insults to the central nervous system appear to occur most frequently during or immediately after surgery. In particular, techniques of support used during neonatal and infant cardiac surgery—cardiopulmonary bypass, profound hypothermia and circulatory arrest—have been implicated as important causes of cerebral injury. This paper will review the effects of bypass and deep hypothermic circulatory arrest on neurodevelopmental outcome.

I. Environmental Contamination and Biochemical Relationships

1975 ◽  
Vol 38 (5) ◽  
pp. 285-300 ◽  
Author(s):  
A. G. HUGUNIN ◽  
R. L. BRADLEY
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Methyl Mercury ◽  
Sea Water ◽  
Inorganic Mercury ◽  
Whole Body ◽  
Irreversible Damage ◽  
Mercury Compounds ◽  
The Central Nervous System ◽  
Pass Through

Mercury is naturally concentrated in geographical belts, but geological cycling has distributed the element in all strata of the earth. Natural concentrations of mercury are approximately 100 ppb in soil, 0.06 ppb in fresh water, 0.01–0.30 ppb in sea water, and 0.003–0.009 μg/m3 in air. Concentrations vary, being highest near mineral deposits. The concentration of mercury in some areas has been significantly increased by human carelessness. An epidemic among Japanese fishing families, death of Swedish wildlife, and discovery of elevated mercury levels in American fish focused attention on this problem. The discovery that certain species are capable of methylating inorganic mercury indicates pollution with any chemical form of mercury is dangerous. Alkylmercurials are the most dangerous form of mercury in the environment. Alkylmercurials are absorbed from the gastrointestinal tract, diffuse across the blood-brain carrier, and pass through the placental membrane in significantly higher proportions than other mercury compounds. The whole body half-life of methyl mercury in humans is 76 ± 3 days compared to half-lives of 37 ± 3 days for men and 48 ± 5 days for women observed for mercuric salts. Not readily broken down, sufficient concentrations of methyl mercury can cause irreversible damage to the central nervous system. Renal damage usually results from high levels of aryl- or alkoxyalkylmercurials and inorganic mercury; however, vapors of elemented mercury can damage the central nervous system. Organic mercury compounds cause chromosome changes, but the medical implications resulting from levels of mercury in food are unknown. The concentration of mercury in red blood cells and hair is indicative of the exposure to alkylmercurials. On a group basis, blood and urine concentrations of mercury may corrrelate with recent exposure to mercury.

scholarly journals XII. An experimental investigation of the central motor innervation of the larynx. Part I. Excitation experiments

1891 ◽  
Vol 48 (292-295) ◽  
pp. 341-342 ◽  
Keyword(s):  
Central Nervous System ◽  
Experimental Investigation ◽  
Nervous System ◽  
Internal Capsule ◽  
Laryngeal Nerve ◽  
Motor Innervation ◽  
Corona Radiata ◽  
Cortical Areas ◽  
The Central Nervous System

In this paper the authors communicate the first part of a series of researches in which they have been engaged from time to time since 1886, on the nature of the representation of the intrinsic laryngeal movements in the central nervous system. Briefly stated, the anatomical arrangement of the laryngeal nerve; centres they believe to be as follows:— a . Cortical areas of representation. b . Connecting fibres in the corona radiata and the internal capsule. c . Bulbar areas of representation.

Neurochemicals and respiratory control during development

1989 ◽  
Vol 67 (1) ◽  
pp. 1-13 ◽  
Author(s):  
I. R. Moss ◽  
J. G. Inman
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Respiratory Control ◽  
Perinatal Period ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Respiratory Effects ◽  
The Central Nervous System ◽  
Plastic Process

During ontogeny, the central nervous system undergoes neuronal growth, regression, and remodeling. The development of neurotransmitter and modulator systems is a plastic process with individual temporal characteristics for each system. These characteristics include the synthesis, degradation, or uptake of neurochemicals and, largely independently, the appearance of their receptors. Message transmission during ontogeny is compounded by the variable development of these systems and by the coexistence and cofunction among these chemicals. Nine neurochemical systems are discussed: adenosine, gamma-aminobutyric acid, opioids, prostaglandins, serotonin, progesterone, substance P, thyrotropin-releasing hormone, and the catecholamines. The possible role of each of these in natural perinatal respiratory control is evaluated according to predetermined criteria. These include the presence of a substance system in respiratory-related regions, physiologically appropriate changes in its concentration in these regions, elicitation of respiratory effects by agonists and antagonists, and abolition with an antagonist of the effect of a substance during its presumed activation by a physiological process. It is suggested that excessive levels of suppressant neuromodulators or an imbalance among neurochemicals can partly explain the special features of respiratory control in the perinatal period.

scholarly journals III. Contributions to the anatomy of the central nervous system of plagiostomata

1886 ◽  
Vol 40 (242-245) ◽  
pp. 10-14 ◽  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Cranial Nerves ◽  
Macroscopic Appearance ◽  
Short Account ◽  
The Third ◽  
Branchial Arches ◽  
The Central Nervous System ◽  
The Subject ◽  
The Difference

After referring to the literature of the subject, the author gives a short account of the macroscopic appearance of the brains of the following species of Plagiostomata, viz., Raja batis, Rhina squatina, Scyllium catulus , and Acanthias vulgaris . He then refers to the distribution of the cranial nerves, especially of the trifacial and vagus, pointing out the resemblance of the distribution of the last-mentioned nerve in Rhina to that described by Gegenbaur in Hexanthus; the difference lying in the fact that in the former the rami branchiales of this nerve, the number of which correspond the number of the branchial arches, divide into two terminal branches only, the rami anteriores and posteriores, the third, the rami pharyngei, being absent.

Cold-induced inhibition of thermal panting in shorn sheep. 1. Effect of intensity of cold exposure

1973 ◽  
Vol 16 (3) ◽  
pp. 271-283 ◽  
Author(s):  
J. Slee
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Heat Stress ◽  
Respiratory Control ◽  
Specific Inhibition ◽  
Merino Sheep ◽  
Delayed Onset ◽  
Blocking Effects ◽  
The Central Nervous System ◽  
Minimum Intensity

SUMMARYThe delayed onset of heat-induced panting (at 42°C) immediately following previous shearing and exposure to cold was studied in 54 Scottish Blackface and 53 Tasmanian Merino sheep.In control sheep (not previously cold-exposed) thermal panting commenced in 15 min. In cold-treated sheep, when the cold was intensified stepwise from +26°C (+30cC being thermoneutral) down to −10°C, using 2-hr exposures, or lengthened from 2 hr to 16 hr at +8°C, the delay (block) to panting increased non-linearly from 40 to 70 min.The minimum intensity of cold required to produce a block (26°C in Merinos, 22°C in Blackfaces) was similar to that inducing peripheral vasoconstriction. More intense vasoconstriction preceded longer blocks, but vasoconstriction sometimes occurred without a subsequent block.Merinos were more sensitive than Blackfaces to the blocking effects of cold, and, once blocked, the effect in Merinos was less easily removed by re-warming.The time taken for cancellation of the heat debt during heat stress could account for half the block. The remainder, a delay of about 30 min, was attributed to a specific inhibition of respiratory control in the central nervous system.

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