Effects of short-term sublethal cadmium exposures on the biochemical composition of dogfish liver.
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Animals↗
Biomedical subjects
L Tort
Publications and source records attributed to L Tort.
Effects on dogfish haematology and liver composition after acute copper exposure.
1. Dogfish Scyliorhinus canicula was subjected to experimental acute copper pollution. At the lowest concentration no changes were recorded on haemoglobin levels whilst decreases of the erythrocyte number and haematocrit was found. 2. At higher concentrations near to the lethal doses, a general reduction of all blood parameters was observed. 3. Liver composition (protein, glycogen and lipid levels) was not affected by any copper concentration, over the duration of the experiments. 4. Results are discussed in relation to physiological responses of fish, acute concentration and metal action.
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Acute toxicity of copper to mediterranean dogfish.
Acute copper toxicity to dogfish (Scyliorhinus canicula) was determined. Median lethal concentrations (LC50) for 24 and 48 hr were respectively 16 and 4 mg/l. These results are compared with those for zinc in dogfish and with the values for copper toxicity in several teleosts obtained by other authors.
Animals↗
Effects of confinement stress and additional zinc treatment on some blood parameters in the dogfish Scyliorhinus canicula.
Several blood parameters were studied in the dogfish Scyliorhinus canicula subjected to different confinement conditions (transport and maintenance) and zinc contamination. Confinement stress significantly decreased erythrocyte counts (RBCC), haematocrit (Ht), haemoglobin (Hb), leucocrit (Lt), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC). Mean corpuscular volume (MCV) did not change with this stress and plasma glucose concentration significantly increased. In fish subjected to confinement stress conditions, Zn treatment significantly decreased Hb, MCH and MCHC and plasma glucose concentration. Ht and MCV did not change and Lt and RBCC significantly increased. Results are discussed related to other stress effects and effects of zinc treatment on fish confined in non-stressful conditions.
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Statistical relations of some blood parameters along recovery from imposed stress in dogfish.
Selected blood parameters (arterial pH, O2 and CO2 tensions, oxygen content, bicarbonate and lactate concentrations, haematocrit, haemoglobin, red blood cell count, mean corpuscular haemoglobin, mean corpuscular volume and mean corpuscular haemoglobin concentration), oxygen consumption and ventilatory frequency were measured 0, 3 and 24 hours after cannulation of the dorsal aorta of 22 dogfish. Correlations were calculated between all pairs of variables along the post-operational recovery period. Results are discussed in terms of the integrated dynamics of the recovery process subsequent to handling, anaesthesia and surgery stress. It is suggested that erythrocyte swelling plays an important role in maintaining tissue oxygen supply during recovery from operational procedures.
Anesthesia↗
Cd-, Zn-, Cu-binding protein in the elasmobranch Scyliorhinus canicula.
A Cd-, Zn-, Cu-binding protein was isolated from the liver of dogfish subjected to environmental experimental contamination (50 ppm Cd). It was also found in liver from untreated fish. This protein has a high absorption at 250 nm and a low absorption at 280 nm, suggesting a mercaptide bond and a lack of aromatic amino acids. The SDS-PAGE pattern and changes in absorption spectrum on adding Cd or lowering pH are found as for mouse MT. The protein contains Cu and Zn in control and Cu, Zn and Cd in treated fish. Cd levels in the protein are significantly higher in females and significantly increase with treatment duration. Copper levels decrease after 96 hr in males and 6 days in females.
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Gill metabolism after chronic subacute zinc treatments.
ATP and lactate concentration of the gill tissue of Scyliorhinus canicula were determined after short-term and long-term subacute zinc exposure. Increase of lactate and decrease of ATP levels were detected after short-term exposure, while no significant changes were observed after long-term treatment, suggesting a recovery process or an activation of compensatory mechanisms.
Adenosine Triphosphate↗
Dogfish liver and kidney tissue respiration after zinc treatment.
Tissue oxygen consumption in liver and kidney of dogfish Scyliorhinus canicula L. were measured by manometric techniques after two types of zinc treatment: in vitro (1, 15, 60 and 180 ppm) and in vivo (subacute 10 ppm/21 days, and acute 80 ppm/24 hr). All in vitro treatments exert a strong inhibitory effect in both tissues. In vivo treatment affects liver tissue respiration at the acute dose. Subacute treatment shows no effects in both tissues. Results are discussed related to previous data on gill tissue respiration and zinc tissue accumulation in the dogfish.
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Metabolic levels in dogfish gill tissue after zinc treatments.
Dogfish were subjected to acute (80 ppm/24 hours) and subacute (10 ppm/21 days) zinc treatments before measuring the ATP, glycogen, protein, and lactate levels. Acute treatment varies significantly the levels of all the metabolites tested while only protein content is significantly lower after subacute treatment. The results are discussed in relation to the hypoxia effect produced by the metal and the related responses of the fish.
Adenosine Triphosphate↗
Oxygen consumption of the dogfish gill tissue following zinc treatment.
1. Oxygen consumption of the dogfish gill tissue has been determined by manometric techniques following different treatments with zinc sulphate. 2. Exposure of the animals to subacute and acute zinc concentrations affects gill tissue respiration. 3. No significant differences in oxygen consumption were found between subacutely treated fish (10 ppm for 4 and 21 days) ad 80 ppm (LC50 48hr) for 24hr exposed animals. 4. Fish treated with 175 ppm (LC50 24hr) for 14 hr greater inhibition of gill tissue respiration than subacutely treated animals. 5. Results are discussed in relation to Zn accumulation in the gill system following the same treatment with zinc sulphate.
Animals↗
Oxygen uptake by dogfish gill tissue after several in vitro zinc treatments.
Oxygen consumption by dogfish gill tissue is measured after several in vitro zinc treatments ranging from low contamination (0.2 ppm) to the 50% lethal concentration at 24 hours (180 ppm). Zinc inhibits respiration from 15 ppm and the inhibition increases along with greater zinc concentrations from 15 to 60 ppm. Thereafter the respiration level becomes stabilized with no further inhibition increases. A similar pattern is described with homogenates but inhibition is stronger and faster, while respiration does not stabilize. The results are discussed in relation to the possible role of the membrane and the toxicological effects caused by zinc.
Animals↗
Is the short-term modulation of heart rate in teleost fish physiologically significant? Assessment by spectral analysis techniques.
Heart rate is an important physiological variable in the control of cardiac output, even in fishes, where the importance of stroke volume has been overemphasized. Except for the myxinoids, the fish heart is innervated by cranial nerve X and the nature of this innervation is mainly inhibitory by parasympathetic fibers, although a sympathetic contribution has also been demonstrated. In mammals, cardiac innervation is not only responsible for the control of mean heart rate but it also modulates the beat-to-beat heart rate changes. These beat-to-beat changes are known as heart rate variability (HRV) and appear to be related to fluctuations in respiration and blood pressure. In this paper we demonstrate the link between cardiac innervation and HRV in several species of teleosts because HRV is greatly decreased after vagotomy or atropinization. In contrast, after abolishing the sympathetic influence with propranolol, only slight changes in total HRV are observed, indicating the restricted importance of the adrenergic innervation in determining phasic changes in HRV despite the significant tonic effect which has been demonstrated. Thus, it appears unlikely that the sympathetic influence will be present in any measured spectral component as suggested previously. Furthermore, clear spectral patterns do not always exist and this may be due to the erratic influence of respiration which is clearly faster than heart rate in all fish species studied. This differs from the slow ventilation frequency displayed by many mammalian species that exerts an influence on a beat-to-beat basis (respiratory sinus arrhythmia). Spectral patterns could also be affected by changing levels of circulating catecholamines, although this is still unproved.
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