scholarly journals CONOPRESSIN G INCREASES BURSTING ACTIVITY IN COMMAND NEURONS MEDIATING RESPIRATORY PUMPING IN APLYSIA CALIFORNICA

1993 ◽  
Vol 174 (1) ◽  
pp. 375-380
Author(s):  
M. Martinez-Padron ◽  
K. Lukowiak
Keyword(s):  
Sea Water ◽  
Intact Animal ◽  
Aplysia Californica ◽  
Respiratory Cycle ◽  
Command Neurons ◽  
Partial Pressures ◽  
Respiratory Pumping ◽  
General Action ◽  
Bursting Activity

Periodic spontaneous gill movements (SGMs) are one of the most obvious of the 21 general action patterns described in the ethogram of Aplysia californica (Leonard and Lukowiak, 1986). SGMs are thought to be a prime component of Aplysia's respiratory cycle (Koester et al. 1974; Byrne and Koester, 1978) and in the intact animal the frequency of SGMs can be modified by changes in the partial pressures of CO2 and O2 of the sea water (Croll, 1985; Levy et al. 1989).

scholarly journals Sensory Control of Respiratory Pumping in Aplysia Californica

1985 ◽  
Vol 117 (1) ◽  
pp. 15-27
Author(s):  
ROGER P. CROLL
Keyword(s):  
Large Deviations ◽  
Sea Water ◽  
Aplysia Californica ◽  
Large Degree ◽  
Mantle Cavity ◽  
Low Ph ◽  
Frequency Change ◽  
Hydrogen Ions ◽  
Sensory Control ◽  
Respiratory Pumping

The frequency of respiratory pumping in Aplysia increases when CO2 is bubbled through the bathing sea water. Air, O2 and N2 do not have this effect. The sensitivity to CO2 may be mediated by receptors which are sensitive to pH changes within the range encountered during hypercapnia. In addition to the frequency change during hypercapnia, increases in the rate of pumping occur after titration to low pH with hydrochloric, acetic, nitric and sulphuric acids, thus indicating sensitivity to changes in the concentration of hydrogen ions and not to any specific anions. High pH and large deviations from normal in the tonicity of the sea water are ineffective in influencing the rate of pumping. The locus of pH sensitivity resides primarily within the mantle cavity. Lesions of the osphradium indicate that this chemosensory organ mediates a large degree of sensory control over respiratory pumping.

scholarly journals Respiratory adaptations in a deep-sea orbiniid polychaete from Gulf of Mexico brine pool NR-1: metabolic rates and hemoglobin structure/function relationships

2002 ◽  
Vol 205 (11) ◽  
pp. 1669-1681 ◽  
Author(s):  
Stéphane Hourdez ◽  
Roy E. Weber ◽  
Brian N. Green ◽  
John M. Kenney ◽  
Charles R. Fisher
Keyword(s):  
Gulf Of Mexico ◽  
Sea Water ◽  
Oxygen Affinity ◽  
Aerobic Metabolism ◽  
Low Oxygen ◽  
Small Diffusion ◽  
Large Numbers ◽  
Partial Pressures ◽  
Hemoglobin Oxygen Affinity ◽  
Rate Of Oxygen Consumption

SUMMARY Methanoaricia dendrobranchiata Blake (Polychaeta; Orbiniidae)occurs in large numbers in association with communities of the mussel Bathymodiolus childressi at hydrocarbon seeps on the Louisiana Slope of the Gulf of Mexico. Its microhabitat can be strongly hypoxic (oxygen is often undetectable) and sulfidic (sulfide concentrations can reach millimolar levels), which may seriously challenge aerobic metabolism. We describe a suite of adaptations to its low-oxygen environment. The worms are capable of regulating their rate of oxygen consumption down to partial pressures of approximately 870 Pa oxygen. This capability correlates with a large gill surface area, a small diffusion distance from sea water to blood, a very high hemoglobin oxygen-affinity (P50=27.8 Pa at 10°C and pH 7.6) and a Bohr effect that is pronounced at high oxygen saturations. When fully saturated, the hemoglobin binds sufficient oxygen for only 31 min of aerobic metabolism. However, these polychaetes can withstand extended periods of anoxia both in the absence and presence of 1 mmoll-1 sulfide(TL50=approx. 5.5 and 4 days, respectively).

scholarly journals On the absorption of carbonic acid by saline solutions

1874 ◽  
Vol 22 (148-155) ◽  
pp. 483-495
Keyword(s):  
Carbonic Acid ◽  
Sea Water ◽  
Point Of View ◽  
Property A ◽  
Partial Pressures ◽  
Cause Of Error ◽  
Series Of Experiments ◽  
Saline Solutions ◽  
Different Parts

In the examination of sea-water, whether it be regarded from a chemical or from a zoological point of view, the determination of and the variations in the amount of carbonic acid in different parts of ocean must always be an object of importance. This is more especially so when a parallel series of observations on the quantity of oxygen present is carried out. At the surface we should expect to find the quantities of these gases following the law of partial pressures; at greater depths, however, where the water for long periods only comes in contact with water, we should expect to find the quantity of oxygen decreasing and that of carbonic acid increasing with the amount of animal life. The investigation from this point of view of the bottom-water, at greater and smaller depths, presents perhaps a more interesting field of observation than that of intermediate depths. Down to nearly 2000 fathoms life is still abundant; below this depth, however, the amount rapidly decreases till, at about 2800 fathoms, it is, for carbonic acid producing purposes, practically extinct. "We have, then, to settle the variation of the carbonic acid with latitude and longitude, with depth, with nature of bottom, and with nature of atmosphere. In order to solve these problems, it is before all necessary to have a reliable method for the determination of the carbonic acid. For the discovery of a cause of error in the old method, and for the invention of a new one, we are indebted to Dr. Jacobsen, of Kiel. Dr. Jacobsen found that sea-water could not, as had been till then assumed, be thoroughly freed from its dissolved carbonic acid by merely boiling in vacuo . He found that it was necessary to boil down almost to dryness before the last traces of carbonic acid could be expelled. Being particularly interested in the matter, I immediately commenced a series of experiments to determine, if possible, the salt or salts to which sea-water owes this peculiar property. A short résumé of the results of these experiments have been published as an appendix to Professor Wyville Thomson’s Depths of the Sea.’

Time-dependent responses of expiration reflex in cats

1986 ◽  
Vol 61 (2) ◽  
pp. 430-435 ◽  
Author(s):  
T. Nishino ◽  
Y. Honda
Keyword(s):  
Electrical Stimulation ◽  
Mechanical Stimulation ◽  
Superior Laryngeal Nerve ◽  
Vocal Folds ◽  
Laryngeal Nerve ◽  
Time Dependent ◽  
Respiratory Cycle ◽  
Partial Pressures ◽  
Spontaneously Breathing ◽  
Stimulation Of

We investigated the effectiveness of the “expiration reflex” in 10 anesthetized spontaneously breathing cats. The expiration reflex was produced by mechanical stimulation of the vocal folds and electrical stimulation of the superior laryngeal nerve at different moments in the respiratory cycle and at various levels of respiratory chemical drive. The effectiveness of the expiration reflex was evaluated from sudden changes in expiratory flow immediately following the stimulation. Both mechanical and electrical stimulations given during early inspiration caused little or no expiratory efforts, whereas stimulations given during early expiration or hypocapnic apnea produced a typical expiration reflex. Changes in arterial CO2 and O2 partial pressures influenced neither the relationships between the stimulation and its effect on the expiration reflex nor the strength of the expiration reflex. These results indicate that the timing of stimulation with relation to the phase of the respiratory cycle is critical to its effect on the expiration reflex and that changes in respiratory chemical drive do not modify the expiration reflex characteristics.

The Swimbladder of Deep-Sea Fish: The Swimbladder Wall is a Lipid-Rich Barrier to Oxygen Diffusion

1980 ◽  
Vol 60 (2) ◽  
pp. 263-276 ◽  
Author(s):  
J. B. Wittenberg ◽  
D. E. Copeland ◽  
F R. L. Haedrich ◽  
J. S. Child
Keyword(s):  
Hydrostatic Pressure ◽  
Partial Pressure ◽  
Sea Water ◽  
Teleost Fishes ◽  
Partial Pressures ◽  
The Difference ◽  
Neutrally Buoyant ◽  
Tissue Fluids ◽  
Considerable Depth ◽  
Sea Fish

The swimbladder of teleost fishes is a gas-filled sac which serves primarily to make the fish neutrally buoyant in sea water, but occasionally assumes other functions. The gas contained in the swimbladder is largely oxygen, at a pressure very close to the external hydrostatic pressure. The difference in gas partial pressure between the gaseous contents of the swimbladder and the blood and tissue fluids is large in fishes living at any considerable depth, for the hydrostatic pressure increases about 1 atm with each 10 m depth, while the partial pressures of gases in sea water and body fluids are relatively independent of depth and together give a pressure of only about 1 atm. The difference in partial pressure of oxygen alone across the wall of the swimbladder of a fish living at 3000 m depth is close to 300 atm.

scholarly journals Do the Extraocular Muscles in the Carp Compensate for Eye Displacements Induced by Respiratory Movements?

1982 ◽  
Vol 99 (1) ◽  
pp. 363-368
Author(s):  
P.J. W. JÜCH
Keyword(s):  
Extraocular Muscles ◽  
Optic Axis ◽  
Respiratory Cycle ◽  
Image Stabilization ◽  
Starting Position ◽  
Pumping System ◽  
Ocular Movements ◽  
Respiratory Pumping ◽  
Respiratory Movements ◽  
Superior Oblique

The eyes in normally respiring carp are induced by elements of the respiratory pumping system to make small displacements in phase with the respiratory cycle. The ocular movements were studied by film analysis during the normal respiratory cycle and the cough. In the course of the movement, the optic axis remains nearly parallel to its starting position. This results in a smaller retinal image shift than would be produced by angular movements. Electromyography of the extraocular muscles showed that the external rectus and superior oblique muscles contribute to image stabilization during strong respiration, and the external rectus and the superior oblique muscles contribute during the cough.

Studies on the Respiration of Sea-Urchin Spermatozoa

1963 ◽  
Vol 40 (4) ◽  
pp. 573-586
Author(s):  
H. MOHRI ◽  
I. YASUMASU
Keyword(s):  
Sea Urchin ◽  
Sea Water ◽  
Platinum Electrode ◽  
Paracentrotus Lividus ◽  
Inhibitory Effect ◽  
O2 Uptake ◽  
Partial Pressures ◽  
Ph Variations ◽  
Hemicentrotus Pulcherrimus

1. The effect of PCOCO2 on the respiration and motility of sea-urchin spermatozoa was studied on Anthocidaris crassispina. Some points were also corroborated on Hemicentrotus pulcherrimus, Pseudocentrotus depressus, Paracentrotus lividus and Sphaerechinus granularis. 2. It was found that any level of CO2 above 1%, both in oxygen and in air, inhibited the O2 uptake of spermatozoa suspended in sea water, measured polarographically with a vibrating platinum electrode. The inhibitory effect paralleled the PCOCO2 and was completely reversed by introducing oxygen or air. 3. pH variations between 8.50 and 6.75 had no influence on O2 uptake, when the pH was stabilized with 0.05 Mhistidine-HCl-NaOH. O2 uptake was, however, reduced to some extent outside this range, especially on the acid side. Although the increase in PCOCO2 is inevitably followed by a decrease in pH, the inhibitory effect of CO2 far exceeds that caused by the reduction in pH. 4. The O2 uptake rate was little affected by the addition of both bicarbonate and carbonate ions to the suspending medium, although the former had a slightly stimulating effect at certain concentrations. 5. In buffered sea water, CO2 had little influence on O2 uptake even at partial pressures as high as 10% which inhibited the bulk of O2 uptake in sea water. 6. Sperm motility was also inhibited by CO2. In this case, too, the inhibition paralleled the PCOMCOM2 and was completely reversible. The effect was more pronounced in air than in oxygen, and in dense sperm suspensions than in dilute ones. 7. These results suggest that gaseous CO2 is the factor responsible for the inhibitory effect. The possible role of CO2 in the dilution phenomena of sea-urchin spermatozoa is discussed.

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