Cutaneous respiration in Octopus vulgaris

1996 ◽  
Vol 199 (11) ◽  
pp. 2477-2483 ◽  
Author(s):  
J Wells

The skin of Octopus vulgaris consumes considerable quantities of oxygen in vitro, averaging 4.55x10(-5)±1.80x10(-5) ml mm-2 h-1 (mean ± s.d.), if a flow is maintained over the skin sample (N=32). The consumption is higher still in vivo, 11.36x10(-5)±2.73x10(-5) ml mm-2 h-1 (N=8), suggesting an additional net import of oxygen through the skin when the blood system is intact. If a substantial boundary layer is allowed to develop, oxygen uptake in vitro falls to 2.09x10(-5)±0.56x10(-5) ml mm-2 h-1 (N=15). The proportion of the animals' total oxygen consumption that cutaneous uptake will represent must thus depend on how much of the skin is exposed and how well it is ventilated. Estimates indicate that some 41 % of the total oxygen requirement of an animal at rest might be satisfied in this manner. During exercise, with water flowing over the entire surface of the animal, cutaneous uptake will increase but is nevertheless likely to form a smaller proportion (about 33 %) of the total uptake. In an animal curled up in its den and digesting a substantial meal, cutaneous uptake could shrink to as little as 3 % of the total. Similar results were obtained in a small number of pilot experiments with a range of octopod, sepioid and teuthoid species.

1987 ◽  
Vol 131 (1) ◽  
pp. 137-157
Author(s):  
D. F. HOULIHAN ◽  
C. AGNISOLA ◽  
N. M. HAMILTON ◽  
I. TRARA GENOINO

A technique is described which allowed the measurement of the oxygen consumption of the isolated heart of Octopus vulgaris. Contraction of the heart resulted in an aortic output and a flow through the heart muscle into coronary veins (the coronary output). The flow and oxygen content of the aortic output and the coronary output were measured with variable input pressures and constant output back pressure (volume loaded), variable output back pressure and constant aortic output (pressure loaded), and during hypoxia. Volume loading of the heart resulted in an increase in aortic output, power output and total oxygen consumption. Pressure loading increased power output and total oxygen consumption of the heart. Exposure to hypoxia decreased the aortic output, power output and total cardiac oxygen consumption. In the response of the heart to reduced work, brought about either by a reduced input pressure or by hypoxic perfusate, the power output was linearly related to the total oxygen consumption of the heart. The oxygen extracted from the coronary output accounted for 80–100% of the total oxygen consumption of the heart. Coronary output amounted to 30% of the total cardiac output at maximum power output. In volume-loaded hearts the volume of the coronary output increased as aortic output increased; in pressure-loaded hearts coronary output increased as power output increased, but aortic output remained constant. In hypoxia, the coronary output increased as the aortic output fell. At a perfusate Po2 of around 50 Torr (1 Torr = 133 Pa), the aortic output ceased although the heart continued to beat and the coronary output continued, accounting for all of the oxygen consumption of the heart. The coronary output flow in vitro therefore has the capacity to be varied independently of the aortic output flow to maintain the oxygen supply to the perfused cardiac muscle.


1983 ◽  
Vol 104 (1) ◽  
pp. 59-71 ◽  
Author(s):  
M.J. WELLS ◽  
J. WELLS

Octopus vulgaris can regulate its oxygen uptake in a closed respirometer down to a Poo2 of less than 70 mmHg. As the tankwater Poo2 falls the hearts slow down. Pulse amplitudes and mean pressures fall in the afferent branchial vessels and in the dorsal aorta. Despite behavioural changes - expansion of the interbrachial web and extension of the arms - that might imply this, the proportion of the total oxygen uptake attributable to cutaneous respiration (less than 13%) does not alter as the external Poo2 falls. The response of the hearts to a low Poo2 is not affected by severing the nerve supply from the central nervous system, or by removal of the heart ganglia. It is evidently determined by oxygen lack and not by the accumulation of CO2 or other metabolites, since the same effects are achieved by placing the animals in water where the Poo2 has been reduced by boiling. The conclusion that regulation does not depend upon circulatory responses to hypoxia is considered in the light of recent work on the changes in blood oxygen affinity associated with acute hypoxia in cephalopods.


1975 ◽  
Vol 62 (2) ◽  
pp. 433-446
Author(s):  
M. J. Wells ◽  
R. K. O'Dor ◽  
S. K. Buckley

1. Protein synthesis occurs at a high rate in the ovaries of maturing Octopus vulgaris and can be measured from the incorporation of [14C]leucine in vivo and in isolated groups of eggs in vitro. 2. Removal of the optic glands in vivo 1--3 days prior to testing markedly reduces amino acid incorporation in vivo or in vitro. After 5 days in vivo incorporation stops. 3. The rate of incorporation in vitro is increased by the addition of optic gland extract. 4. Analysis of the kinetics of leucine uptake and incorporation in vitro indicates that the hormone has an effect on the inward transport of leucine which is independent of its action on protein synthesis. 5. Electron-microscope studies of the follicle cells and ova show that the former are the site of protein synthesis. 6. Changes in either uptake or incorporation into protein by the follicle cells can be used as a qualitative biolobical assay for the optic gland hormone. Uptake is very easy to measure but incorporation is the more sensitive parameter. Either is potentially suitable as a quantitative assay for this and perhaps also for other molluscan gonadotropins.


1984 ◽  
Vol 7 (1) ◽  
pp. 11-21
Author(s):  
L. Mor ◽  
S. Sideman ◽  
M. Mihich ◽  
A. Tzipiniuk ◽  
S. Lupovich ◽  
...  

The study demonstrates that different individuals (monkeys) need different heparin doses so as to avoid either clotting or bleeding when an extracorporeal blood system is involved. The linear correlation between PT and WBPTT values enables to utilize the latter for monitoring the heparin level in the blood. One procedure is based on the application of the Gotch and Keen intravenous heparinization model in its steady state limit by utilizing the pre-treatment evaluation of k/S, the ratio of the elimination rate constant to the individual's sensitivity to heparin. A second procedure involves the direct heparinization of the extracorporeal system. The heparin infusion rate is monitored through the arterial WBPTT values after relating the individual's PT or WBPTT values to the in vitro heparin concentration in the blood. In vitro and in vivo study of the effect of hemoperfusion through a column containing anion exchange particles on the amount and rate of heparin administration indicates that only the in vivo results are meaningful. The sharp response of WBPTT to relatively small changes of citrate concentration in the blood precludes individual monitoring by WBPTT. Work on the advantage of utilizing heparin together with citrate is required.


1999 ◽  
Vol 202 (6) ◽  
pp. 697-709 ◽  
Author(s):  
A. Salama ◽  
I.J. Morgan ◽  
C.M. Wood

The nature of the linkage between between branchial ammonia excretion (JAmm) and unidirectional Na+ influx (JNain) was studied in the freshwater rainbow trout (Oncorhynchus mykiss). Arterial plasma total [ammonia], PNH3 and JAmm were all elevated approximately threefold by intravascular infusion for 24 h with either 70 mmol l-1 (NH4)2SO4 or 140 mmol l-1 NH4HCO3 at a rate of approximately 400 micromol kg-1 h-1. Both treatments markedly stimulated JNain. NH4HCO3 induced metabolic alkalosis in the blood plasma, whereas (NH4)2SO4 caused a slight metabolic acidosis. Experiments with Hepes-buffered water (5 mmol l-1) under control conditions demonstrated that increases in gill boundary layer pH were associated with decreases in both JNain and JAmm. Thus, the stimulation of JNain caused by ammonium loading was not simply a consequence of a Na+-coupled H+ extrusion mechanism activated by internal acidosis or by alkalosis in the gill boundary layer. Indeed, there was no stimulation of net acidic equivalent excretion accompanying NH4HCO3 infusion. Michaelis-Menten kinetic analysis by acute variation of water [Na+] demonstrated that both infusions caused an almost twofold increase in JNamax but no significant change in Km, indicative of an increase in transporter number or internal counterion availability without an alteration in transporter affinity for external Na+. The increase in JNain was larger with (NH4)2SO4 than with NH4HCO3 infusion and in both cases lower than the increase in JAmm. Additional evidence of quantitative uncoupling was seen in the kinetics experiments, in which acute changes in JNain of up to threefold had negligible effects on JAmm under either control or ammonium-loaded conditions. In vitro measurements of branchial Na+/K+-ATPase activity demonstrated no effect of NH4+ concentration over the concentration range observed in vivo in infused fish. Overall, these results are consistent with a dominant role for NH3 diffusion as the normal mechanism of ammonia excretion, but indicate that ammonium loading directly stimulates JNain, perhaps by activation of a non-obligatory Na+/NH4+ exchange rather than by an indirect effect (e.g. Na+-coupled H+ excretion) mediated by altered internal or external acid-base status.


Blood ◽  
1996 ◽  
Vol 87 (1) ◽  
pp. 67-72 ◽  
Author(s):  
M Tavian ◽  
L Coulombel ◽  
D Luton ◽  
HS Clemente ◽  
F Dieterlen-Lievre ◽  
...  

Abstract Hematopoiesis is established from circulating blood stem cells that seed the embryonic rudiments of blood-forming tissues, a basic notion in developmental hematology. However, the assumption that these stem cells originate from the extraembryonic mesoderm, where primitive hematopoiesis is initiated by intrinsic precursors, has been reconsidered after analysis of blood cell development in avian embryo chimeras: yolk-sac-derived stem cells do not contribute significantly to the definitive blood system, whose first forerunners develop independently along the ventral aspect of the embryonic aorta. Recently, the homologous intraembryonic tissues of the mouse have been submitted to sensitive in vivo and in vitro assays, which showed that they also harbor multipotential hematopoietic stem cells. We have now identified a dense population of hematogenous cells, marked by the surface expression of the CD34 glycoprotein, associated with the ventral endothelium of the aorta in the 5-week human embryo. Therefore, we extend to the human species the growing evidence that intraembryonic hematopoietic cells developing independently of the yolk sac might be the real stem of the whole blood system.


1991 ◽  
Vol 157 (1) ◽  
pp. 523-540 ◽  
Author(s):  
C. AGNISOLA ◽  
D. F. HOULIHAN

The effect of increasing oxygen supply on the perfused systemic heart of Octopus vulgaris (Lam.) by using oxygenated or haemocyanin-containing perfusates was investigated. Providing aerated blood or seawater solutions of haemocyanin that were comparable with blood in oxygen-carrying capacity improved the performance of the isolated heart compared with that of hearts perfused with aerated sea water. Aortic outputs were similar to in vivo values (44ml min−1 g−1) at close to in vivo values of preload and afterload owing to an increase in both heart rate (from 24.0 to 38.4beatsmin−1) and stroke volume (from 0.69 to 1.10ml g−1). Coronary flow fell in these conditions, becoming 2.5% of the aortic output (against 24% with aerated sea water). A parallel increase in coronary resistance was found. Oxygenated sea water also improved the performance of the heart, mainly by improving the stroke volume. Both with haemocyanin solutions or blood and with oxygenated sea water, the isolated heart was able to do more work at lower preloads compared with the hearts perfused with aerated sea water. Power output was linearly related to total oxygen consumption and carbon dioxide production. The major site of oxygen consumption was the coronary bed. Haemocyanin released about 70% of the bound oxygen as it passed through the ventricular wall. Note: Present address: Department of Zoology, University of Aberdeen, Aberdeen AB9 2TN, Scotland, UK.


2021 ◽  
Author(s):  
V R Sanal Kumar ◽  
Vigneshwaran Sankar ◽  
Nichith Chandrasekaran ◽  
Sulthan Ariff Rahman Mohamed Rafic ◽  
Ajith Sukumaran ◽  
...  

Abstract Although the interdisciplinary science of nanotechnology has been advanced significantly over the last few decades there were no closed-form analytical models to predict the three-dimensional (3D) boundary-layer-blockage (BLB) factor, of diabatic flows (flows involves the transfer of heat) passing through a nanoscale tube. As the pressure of the diabatic nanofluid and/or non-continuum-flows rises, average-mean-free-path diminishes and thus, the Knudsen number lowers heading to a zero-slip wall-boundary condition with the compressible viscous flow regime in the nano scale tubes leading to Sanal flow choking [PMCID: PMC7267099; Physics of Fluids, DOI: 10.1063/5.0040440] creating a physical situation of the sonic-fluid-throat effect in the tube at a critical-total-to-static pressure ratio (CPR). Herein, we presented a closed-form-analytical-model, which is capable to predict exactly the 3D-BLB factor at the Sanal flow choking-condition of nanoscale diabatic fluid flow systems at the zero-slip-length. The innovation of Sanal flow choking model in the nanoscale fluid flow system is established herein through the entropy relation, as it satisfies all the conservation laws of nature. The exact value of the 3D-BLB factor in the sonic-fluid-throat region presented herein for each gas is a universal benchmark data for performing high-fidelity in silico, in vitro and in vivo experiments for the lucrative design optimization of nanoscale fluid flow systems in gravity and microgravity environments and also for drug discovery for prohibiting asymptomatic cardiovascular diseases in Earth and human spaceflight <doi.org/10.2514/6.2021-0357>. Note that the relatively high and low-blood-viscosity (creating high turbulence) leads to the Sanal flow choking causing asymptomatic cardiovascular diseases. Such diseases in the cardiovascular system can be negated by maintaining the systolic-to-diastolic blood pressure ratio lower than the CPR <10.1002/gch2.202000076>. The CPR is regulated by the heat capacity ratio (HCR) of the fluid. Note that HCR is the key parameter, which could control simultaneously blood viscosity and turbulence. The physical insight of the boundary-layer-blockage persuaded nanoscale Sanal flow choking in diabatic flows presented in this article sheds light on finding solutions to numerous unresolved scientific problems in physical, chemical and biological systems carried forward over the centuries because the closed-form analytical model describing the phenomenon of Sanal flow choking is a unique scientific language of the real-world-fluid flows. More specifically, mathematical models presented herein are capable to forecast the limiting conditions of deflagration to detonation transition (DDT) in nanoscale systems and beyond with confidence. Additionally, the Sanal flow choking condition will forecast the asymptomatic-hemorrhage and acute-heart-failure https://www.ahajournals.org/doi/10.1161/str.52.suppl_1.P804. Briefly, the undesirable Sanal flow choking causing detonation and hemorrhagic stroke can be negated by increasing the HCR of the fluid.


2018 ◽  
Vol 106 ◽  
pp. 952-963 ◽  
Author(s):  
Rabeb Ben Slama-Ben Salem ◽  
Naourez Ktari ◽  
Intidhar Bkhairia ◽  
Rim Nasri ◽  
Leticia Mora ◽  
...  

1980 ◽  
Vol 84 (1) ◽  
pp. 319-334
Author(s):  
M. J. Wells ◽  
K. Mangold

Recordings of pressure and frequency were made from the hearts of free-moving Octopus vulgaris. The effects of extracts from neurosecretory endings in the anterior vena cava (AVC) and the pharyngo-ophthalmic vein (POV), injected through fine cannulae into a branchial heart, efferent branchial vessel or the dorsal aorta, were studied and compared with the effects of acetylcholine, 5-hydroxytryptamine, adrenaline, histamine and tyramine. AVC and POV extracts each produce a different spectrum of effects, unlike those of any of the drugs tested. AVC extract is effective at doses of less than 2% of the material extractable from a single vein per kg, increasing the force and amplitude of the heartbeats. With a natural release point just upstream of the branchial hearts the AVC material must be relevant to the normal performance of the hearts. POV extract is effective only at doses equivalent to several veins per kg, and is unlikely to have a role in cardiac regulation. Section of the visceral nerves did not affect the action of drugs or extracts, indicating that effects were not indirectly mediated via the CNA. Further experiments were made with hearts and the aorta in vitro with effects that did not always parallel those found in vivo. Reasons for these differences are discussed.


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