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At least 37 records · Page 2Linked to original sources
PubMed1978

Stability and the biological activity of eel calcitonin in rats.

Hypocalcemic effect in rats of eel calcitonin was more persistent that that of porcine calcitonin and it was as persistent as that of salmon calcitonin I. Eel calcitonin was more stable than porcine or salmon calcitonin I when incubated in vitro with rat or human serum. Incubation in vitro with rat kidney or liver extract for 1 hour at 37 degrees C caused an almost complete inactivation of porcine calcitonin. On the other hand, both eel and salmon calcitonin I were inactivated less markedly and in the similar manner. The relationship between the hypocalcemic effect of calcitonins and the inactivation is discussed.

Animals↗
PubMed1977

Gas deposition by counter-current multiplication in the eel swim-bladder: experimental verification of a mathematical model.

1. Blood pO2 along the rete of eel has been investigated with a microelectrode, the swim-bladder gas being replaced by air. 2. When the eel does not secrete gas, the pO2 profile is flat, whereas in actively secreting eel the pO2, along the rete has a maximum of approximately 1 atm near the bladder pole of the rete. 3. The findings confirm predictions of a mathematical model for counter current multiplication in the swim-bladder.

Air Sacs↗
PubMed1977

[Electrical activity of the brain of the eel (Anguilla anguilla L.) subjected to hypoxia and hypercapnia].

The effects of hypoxia and hypercapnia on the electric activity of cerebral vesicles have been studied in 48 unrestrained eels placed in water in a soundproof location. 1. Hypoxia (PwO2 less than 5 torr) was well endured for 8 hours after which sharp bursts appeared, rapidly followed by cerebral death. 2. Hypercapnia (PwCO2 congruent to 14 torr) gave an amplitude decrease in cerebral activity beginning with the first hour, and after 8 hours there was an appearance of slow waves which progressively invaded the recording while the latency of average VER increased. 3. The large resistance of eels to hypoxia, is discussed in relation to the importance of anaerobic glycolysis in fish. The effects of hypercapnia on cerebral electric activity in eels are comparable to those observed in mammals and may be due to metabolic and electrolytic modification in CRL and in nervous cells.

Animals↗
PubMedDate not supplied

Effect of deterlon (DBS) on the electrocardiogram of eel Anguilla anguilla (L).

Effect of Deterlon (DBS) on the electrocardiogram of eel Anguilla anguilla (L). Acta Physiol. Pol. 1977, 28 (2): 179--186. The investigations of the effect of a detergent Deterlon-DBS present in industrial and community sewage on ECG changes in the eel Anguilla anguilla (L) showed that it causes disturbances in the impulse-generating centres and in the mechanism of impulse conduction in the heart. It was found that the threshold concentration of Deterlon-DBS in aqueous medium is 3 mg SA/1 for the eel, the lethal concentration lying in the range of 60--100 mg SA/1.

Animals↗
PubMed1976

Physiological properties of eel haemoglobin: hypoxic acclimation, phosphate effects and multiplicity.

Unlike the whole body oxygen affinity, which adapts readily to environmental oxygen tensions, haemoglobins, prepared from normoxic- and hypoxic-accimated eels (Anguilla anguilla) show no adaptive changes in oxygenation properties or in multiplicity. Hypoxic acclimation is, howeveer, accompanied by a strong decrease in red cell nucleoside triphosphates, particularly guanosine triphospphate (GTP), which depresses oxygen affinity of the composite and component haemoglobins more strongly than does the concurring ATP. The effects of pH, temperature and salts on the oxygenation properties of the (isolated) haemoglobins are reported, discussed in relation to the varying environmetal conditions encountered by eels, and compared with data on American and Japanese eels (A. rostrata and A. juponica, respectively.

Adenosine Triphosphate↗
PubMed1976

[Feeding and growth of elvers of anguilla Anguilla L. (eel-like teleosten fish) experimentally reared at various temperatures in the laboratory].

In France, there are few researches carried out on the eel's elvers rearing. So, we have undertaken to do, in a first time, a study of their alimentation and growth, in relation to the temperature, at laboratory. The structure of european eels' elvers population, drawn in its natural environment, shows a polymodal frequency distribution of individual weights. The temperature has a direct effect on general metabolism of animals and consequently on their growth. For temperatures included between 10 degrees C and 25 degrees C, any increase of this factor induced an individual activity more important. The quantity of ingested food and its rapidity of utilization, the precocity of alimentary behaviour, are in relation with temperature. The best growth is obtained at 25 degrees C. It seems that this temperature permits to have a very low mortality. From 10 degrees C and below, growth is inhibited, the individual activity and the alimentary taking are very low or non-existent. However, if temperature is elevated, from 11,5 degrees C, growth can start off again, animals are very active and an alimentary behavious is observed. At least, rearing of the european eels' elvers is possible with a salt water (salinity : 32 p. 1000); this system permits suppress in totality fungi desease (saprolegnia).

Anguilla↗
PubMed1976

The effects of acetylcholine, biogenic amines and other vasoactive agents on the cardiovascular functions of the Eel, Anguilla japonica.

The blood pressure in the cardinal vein, cardiac chambers and ventral and dorsal aortae have been recorded from conscious eels in water. At low doses, acetylcholine reduced the heart rate but increased the transbranchial differential blood pressure. The effects were abolished by atropine but not by tubocurarine. At doses in excess of 0.1 mug/kg, a secondary rise in arterial blood pressure was observed which could be abolished by bretylium, phentolamine or phenoxybenzamine. Catecholamines did not affect the heart rate although a transient bradycardia due to reflex inhibition could be observed with adrenaline and noradrenaline. Catecholamines increased the cardiac contractile force through an alpha-adrenergic mechanism which was blocked by phentolamine but not by propranolol. The relative potency was noradrenaline greater than adrenaline greater than isoprenaline. A beta-adrenergic receptor located in the branchial circulation led to vasodilation and decrease in transbranchial differential pressure. Both alpha-(vasoconstriction) and beta-(vasodilation) adrenergic receptors were present in the systemic circulation. Dopamine, 5-HT, GABA and bradykinin caused bradycardia abolishable by vagotomy or atropine treatment. Angiotensin II was hypertensive but did not affect the heart rate nor the transbranchial differential pressure. Tyramine caused release of endogenous catecholamines. With repeated doses, tachyphylaxis to the drug was observed. Histamine was without any obvious cardiovascular effects in the eel.

Acetylcholine↗
PubMed1978

Prolactin, hypercalcemia and corpuscles of Stannius in seawater eels.

In intact eels in sea water (SW), ovine prolactin (PRL) treatment induces hypercalcemia, but its mechanism of action, which is discussed, remains to be defined. Corpuscles of Stannius (CSt) are modified simultaneously: two cell categories then become evident. The first cell type (type 1) predominates; it has an oval shape and large granules, it shows a nuclear and nucleolar hypertrophy and a mitotic activity, and appears greatly stimulated by PRL; it may elaborate a hypocalcemic factor (hypocalcin) which would compensate for the PRL-induced hypercalcemia. A similar effect, although slightly less intense, is detected in hypophysectomized-PRL treated eels in SW. A second cell type (type 2), is more elongated, smaller in size, and has an oval nucleus and fine granules. Scarcely less active in SW, it is significantly stimulated by PRL despite an increased blood sodium and potassium level. This experiment does not help to clarify its function.

Animals↗
PubMed1978

The eel retina. Receptor classes and spectral mechanisms.

Light and electron microscopy revealed that there are both rods and cones in the retina of the eel Anguilla rostrata. The rods predominate with a rod to cone ratio of 150:1. The spectral sensitivity of the dark-adapted eyecup ERG had a peak at about 520 nm and was well fit by a vitamin A2 nomogram pigment with a lambdamax = 520 nm. This agrees with the eel photopigment measurements of other investigators. This result implies that a single spectral mechanism--the rods--provides the input for the dark-adapted ERG. The spectral sensitivity of the ERG to flicker in the light-adapted eyecup preparation was shifted to longer wavelengths; it peaked at around 550 nm. However, there was evidence that this technique might not have completely eliminated rod intrusion. Rod responses were abolished in a bleached isolated retina preparation, in which it was shown that there were two classes of cone-like mechanisms, one with lambdamax of 550 nm and the other with lambdamax of less than 450 nm. Ganglion cell recording provided preliminary evidence for opponent-color processing. Horizontal cells were only of the L type with both rod and cone inputs.

Animals↗
PubMed1977

Immunological stability in vitro and in vivo of eel calcitonin.

The immunological activity of eel calcitonin was more persistent than that of porcine and human calcitonin when incubated in vitro with rabbit serum, human serum, liver homogenate or kidney homogenate, respectively. Both eel and human calcitonin were more stable than porcine calcitonin when injected iv into rabbits.

Animals↗
PubMed1976

[Cardiorespiratory effects of exogenous hypercapnia in eels].

The study of electrocardiogram and opercular movement records, from eels exposed for prolonged periods to hypercarbic water (saturation by the gaseous mixture 2% CO2, 98% air) shows that 1) heart rate is not significantly changed; 2) the duration of spontaneous apnea phases and the magnitude of opercular movements during ventilatory phases are increased under hypercapnic conditions. Because the integrated records of opercular movements only give an arbitrary estimate of changes in ventilation rate, direct measurements of the ventilation volume were performed in order to state the way of the dominant action of CO2. This method allows us to conclude that exogenous hypercapnia significantly decreases the ventilatory rate in eels.

Animals↗
PubMedDate not supplied

[Seasonal variations in epinephrine (E) and norepinephrine (NE) levels determined in organs of eel (author's transl)].

E and NE concentrations were measured by using a spectrofluorimetric method in various organs of eels, for a one year period. NE was found at higher levels than E in the whole brain, the heart, and the spleen. Maximal E levels occurred in kidney. Moreover (E + NE) sum is 40 to 190% higher than during spring and summer when compared to autumn and winter levels. According to the fact that seasonal variations of catecholamines were not found in the eel plasma, these results suggest that the observed seasonal variations can be related to fluctuation in CA amounts localized in synaptic structures.

Animals↗
PubMed1979

Salinity adaptation in the snake eel Pisoodonophis boro (Ham-buch).

The snake eel Pisoodonophis Boro (Family Ophichthidae) burrows, causing leaks in the bunds and damaging the salterns and paddy fields adjoining estuaries. The animal's capability to withstand brine in salterns and fresh water in paddy fields was determined from laboratory experiments. The eel tolerated salinities ranging from deionized water to 75%. Adaptation to fresh water as well as full strength seawater was completed within 24 h. The concentration of sodium and chloride in the blood varied by 10--20% on transfer from seawater to fresh water. P. boro can survive in paddy fields but not in salterns. However, their occurrence in both is described as a rare phenomenon and not obligatory.

Adaptation, Physiological↗
PubMed1977

[Studies on the morphology of blood of the European eel (Anguilla agnuilla). III. Studies on monocytic and lymphoid cells].

Investigations concerning the monocytic and lymphocytic cell series were carried out on the peripheral blood and dabbings of the kidney, the spleen and intestines of healthy eels (anguilla anguilla), and eels taken ill with vibrio anguillarum. By means of histological, cytochemical, phaseoptical, and electronmicroscopical examinations independent development lines of the monocytes and lymphocytes were established. The place of origination for the monocytes was found to be the kidney, for the lymphocytes the spleen and the intestines additionally. The evidence of the cytochemical assay of enzymes for the differentiation of these blood cells and their cellular systems is primarily dependent on the distribution of the activity of the unspecific esterase, the naphthol-AS-D-chloroacetate-esterase, the peroxidase and the alkalic phosphatase. Macrophages were - on the basis of enzymocytochemical results - seen as derivatives of the monocytes. Plasma cells and lymphoid cells are transformation forms of the lymphocytes. Our results emphasize the significance especially of cytochemistry for the hematological diagnostics of fish diseases.

Animals↗
PubMed1975

[Structural modifications of the esophagus linked to osmoregulation in eels].

In comparison with the fresh-water Eel (Anguilla anguilla L.), the oesophagus of the sea-water Eel displays an almost complete regression of the multilayered epithelium and consequently the disappearance of mucous cells. In contrast, a large development of a columnaŕ epithelium is associated with a tremendous proliferation of the subepithelial vascularization. These modifications enable one to interpret the changes in ionic permeability of the oesophagus during transfer from freshwater to seawater.

Animals↗
PubMed1977

Pancreatectomy in a teleost fish, Anguilla rostrata (American eel).

A technique for pancreatectomy was described for the American eel. In this fish, the operation was not followed by the typical signs of diabetes mellitus. Histodensitometric determination of liver glycogen showed no major differences between operated controls and pancreatectomized eels. The absence of a specific hyperglycemia, previously reported with the hexokinase method, was confirmed with the glucose oxidase technique; however, the more specific hexokinase method gave consistently lower values. Breakdown of adipose tissue and hyperlipemia were absent.

Animals↗
PubMed1977

Relative estimation of ventilatory fow rate in the eel (Anguilla anguilla L.)

Freshwater eels (Anguilla anguilla L.) were experimented on in order to measure ventilatory flow rate (by means of a direct method of collecting expired water), and simultaneously, to record sub-opercular pressure changes and opercular displacements (operculogram). Significant correlations (p less than 0.01) were found between the ventilatory flow rate (V) and various characteristics of operculiogram records. The relationships which are significant in each fish experimented on are; V = a(f.lo) + b; V = a(f.Ao) % b and V = a(f.Ao2) + b(f: ventilatory frequency: Ao and lo: mean amplitude and result of integration of opercular tracings). Considering the technical difficulties in measuring the ventilation flow rate of the eel, the easier operculographic recording methods lead to a correct estimation of relative changes in ventilatory flow rate, by using the refined relationship: V = a(Ao1.63).

Animals↗