Sodium Regulation in the Crayfish Astacus Fluviatilis

1960 ◽  
Vol 37 (1) ◽  
pp. 113-128
Author(s):  
G. W. BRYAN

1. In external sodium concentrations of up to 100 mM./l. the blood sodium concentration of Astacus is only slightly increased. As the external level approaches or exceeds the normal blood sodium concentration of 200 mM./l. so the increase becomes more marked. Similarly, there is an increase in urine sodium concentration. This net gain of sodium is accompanied by a considerable rise in sodium outflux as shown by 22Na. At external concentrations exceeding 300 mM./l., blood and urine concentrations rise to a similar level and active sodium movements appear to cease. 2. With increased blood sodium concentration the level in the muscles rises also. This relationship is not one of simple proportion and at high concentrations there is relatively more sodium in the muscles. 3. In artificial tap water animals with a high blood concentration lose sodium until the normal level is regained. This net loss is due to influx being much lower and outflux much higher than normal. Of the outflux, up to 70% is initially due to renal losses and losses over the body surface are higher than normal due to the excess sodium in the blood. 4. From the results given in this and previous papers the way in which sodium balance may be achieved under normal conditions is discussed.

1960 ◽  
Vol 37 (1) ◽  
pp. 83-99 ◽  
Author(s):  
G. W. BRYAN

1. In Bristol tap water containing 0.4 mM./l. sodium and artificial tap water containing 2 mM./l. sodium, Astacus maintains a blood sodium concentration of about 203 mM./l. This value was not markedly affected by starvation periods of up to a month. 2. Methods of taking small blood and urine samples from individual crayfish at intervals over several hundred hours have been described. 3. Under steady state conditions, curves for the uptake and loss of 22Na by the blood are described by equations derived for a one-compartment system. 4. The volume of this single compartment, which exchanges sodium with the medium, is larger than the actual blood volume by an amount roughly equivalent to the sodium in the tissues. Exchange of sodium between the blood and tissues is probably very rapid. 5. Sodium losses in the urine account for about 6% of the total sodium outflux found using 22Na. The urine sodium concentration of about 6 mM./l. was temporarily increased by conditions such as heavy feeding when the blood may have gained additional sodium. 6. Potential difference measurements across the body surface indicate that the high blood sodium concentration is maintained by active uptake of sodium.


1960 ◽  
Vol 37 (1) ◽  
pp. 100-112
Author(s):  
G. W. BRYAN

1. In distilled water or artificial tap water with a very low sodium concentration, sodium uptake by Astacus is prevented or reduced and 22Na outflux is subnormal. This is accounted for to only a small extent by reduced renal sodium losses. 2. Sodium-depleted animals replaced in artificial tap water regain sodium in a roughly exponential manner. This is shown by 22Na to be the result of a considerable increase in sodium influx coupled with an increased but lower outflux. 3. Sodium outfiux appears to consist of three components: urine losses, passive diffusion losses over the body surface and what may be an ‘exchange diffusion’ component which is high during high influx and minimal in distilled water. This latter component represents about 30% of sodium exchange under normal conditions. 4. Eyestalk removal did not affect the ability of Astacus to absorb sodium. 5. In starved animals the gills take up most of the sodium absorbed and the gut is relatively unimportant. 6. Silver staining of the gills is a passive process and the cuticle of the branchial filaments of the gill stem is selectively stained. This region would be a suitable site for ion uptake mechanisms.


1970 ◽  
Vol 53 (1) ◽  
pp. 147-163 ◽  
Author(s):  
PETER GREENAWAY

1. Sodium regulation in normal, sodium-depleted and blood-depleted snails has been investigated. 2. Limnaea stagnalis has a sodium uptake mechanism with a high affinity for sodium ions, near maximum influx occurring in external sodium concentrations of 1.5-2 mM-Na/l and half maximum influx at 0.25 mM-Na/l. 3. L. stagnalis can maintain sodium balance in media containing 0.025 mM-Na/l. Adaptation to this concentration is achieved mainly by an increased rate of sodium uptake and a fall of 37 % in blood sodium concentration, but also by a reduction of the sodium loss rate and a decrease in blood volume. 4. A loss of 23% of total body sodium is necessary to stimulate increased sodium uptake. This loss causes near maximal stimulation of the sodium uptake mechanism. 5. An experimentally induced reduction of blood volume in L. stagnalis increases sodium uptake to three times the normal level. 6. About 40% of sodium influx from artificial tap water containing 0.35 mM-Na/l into normal snails is due to an exchange component. Similar exchange components of sodium influx were also observed in sodium-depleted and blood-depleted snails in the same external sodium concentration.


1968 ◽  
Vol 48 (2) ◽  
pp. 359-380
Author(s):  
D. W. SUTCLIFFE

1. Sodium uptake and loss rates are given for three gammarids acclimatized to media ranging from fresh water to undiluted sea water. 2. In Gammarus zaddachi and G. tigrinus the sodium transporting system at the body surface is half-saturated at an external concentration of about 1 mM/l. and fully saturated at about 10 mM/l. sodium. In Marinogammarus finmarchicus the respective concentrations are six to ten times higher. 3. M. finmarchicus is more permeable to water and salts than G. zaddachi and G. tigrinus. Estimated urine flow rates were equivalent to 6.5% body weight/hr./ osmole gradient at 10°C. in M. finmarchicus and 2.8% body weight/hr./osmole gradient in G. zaddachi. The permeability of the body surface to outward diffusion of sodium was four times higher in M. finmarchicus, but sodium losses across the body surface represent at least 50% of the total losses in both M. finmarchicus and G. zaddachi. 4. Calculations suggest that G. zaddachi produces urine slightly hypotonic to the blood when acclimatized to the range 20% down to 2% sea water. In fresh water the urine sodium concentration is reduced to a very low level. 5. The process of adaptation to fresh water in gammarid crustaceans is illustrated with reference to a series of species from marine, brackish and freshwater habitats.


1975 ◽  
Vol 62 (1) ◽  
pp. 121-139
Author(s):  
DA Wright

Sodium regulation was studied in fourth instar larvae of Chironomus dorsalis and Camptochironomus tentans. Both maintain a body sodium level well above that of the surrounding medium. The haemolymph contains approximately 90% of total body sodium and approximates to a single compartment freely exchanging sodium with the external medium. The anal papillae play a primary role in sodium regulation, the gut being in secondary importance. Sodium regulation in both species is comparatively insensitive to alterations in acclimatization temperature. C. dorsalis and C. tentans are capable of maintaining sodium balance in media containing 10 mumole Na and 25 mumole Na respectively. When exposed to several changes of distilled water, C. tentansis capable of reducing sodium loss by elaboration of a more dilute urine. This is apparently,supplemented by a reduction in the permeability of the body surface. Activation of sodium uptake in both species is comparatively sluggish, with influx reaching a maximum only after the loss of greater than 30% body sodium.


1974 ◽  
Vol 61 (3) ◽  
pp. 719-736
Author(s):  
D. W. SUTCLIFFE

1. The principal features of the sodium regulatory mechanism are compared in Asellus communis Say, A. aquaticus (L.) and A. meridianus Rac. 2. Water content and total concentrations of sodium and chloride are similar in the three species, but they differ with respect to values for Kmax, Km, the loss rate, and the minimum sodium balance concentration. 3. It is suggested that A. meridianus, A. aquaticus and A. communis represent a natural series of increasing adaptation to fresh water. A. communis from North America is completely adapted to fresh water. It has the lowest loss rate, the lowest maximum saturation level (Kmax) for sodium influx, and the highest affinity (low Km value) for sodium ions in the transporting system at the body surface. In many respects A. meridianus resembles freshwater populations of Mesidotea entomon and Gammarus duebeni, and may therefore have had a relatively short history in fresh water.


Author(s):  
Ishtar Munim Nassir ◽  
Abaas Noor Al-Sharify ◽  
Hasan Alwan Baiee

Background Human milk is the only source of food for infants during the first four to five months of their life. Some chemicals compood can be transferred from the body stores and from blood into the breast milk of a lactating mother. Objectives       To determining and measurements of Nickel leval the human milk and to identify the associations of certain potential variables with the concentrations of these heavy metals. Subjects and Methods        This is a cross-sectional study carried included a milk test by a randomly selected (68) women apparently healthy lactating women, who attended Babylon  Maternity & children hospital in Al – Hilla city during the period mid of February through the end of April 2012. Breast milk was collected and analyzed to detect and measure Nickel using atomic absorption. A questionnaire paper was prepared to recorded the demographic variables. Weights and heights were measured to calculate the Body Mass Index. Results       This study revealed that the mean concentrations of Nickel in the human milk was (23.83±15.57 ppb) which was remarkably high as compared with the concentrations reported by other studies done in other countries. The study shows that there was a statistically significant association (p<0.0s) between  the high concentrations of  Nickel and the followings associates ; living in urban regions ,living near highways , living near industrial regions and drinking river or tap water, being younger (<3oyears of  age) or heaver increase weight and being cigarettes smokers. The prevalence rates of lactating mothers with abnormal concentrations of was 99%and 93% respectively indicating the serious environmental pollution in Hilla city. Conclusion        Breast milk of lactating mothers in Hilla city is abnormally contaminated with; Nickel this public health problem need to be addressed.


1967 ◽  
Vol 46 (3) ◽  
pp. 519-528
Author(s):  
D. W. SUTCLIFFE ◽  
J. SHAW

1. The sodium balance mechanism of Gammarus lacustris in fresh water is virtually identical with that found in G. pulex. 2. The sodium transporting system at the body surface has a very high affinity for sodium ions. The system is half-saturated at an external concentration of about 0.14 mM/l. and fully saturated at about 1 mM/l. sodium. 3. The lowest external concentration at which sodium balance was maintained was 0.06 mM/l. 4. Both the total sodium loss rate and the sodium influx rate remained approximately constant in animals acclimatized to the range of external concentrations from 2 to 0.3 mM/l. NaCl. At lower concentrations the loss rate was reduced and the influx increased by a factor of about 1.5. 5. Changes in the sodium influx and loss rates are very closely linked together, and it is shown how these changes are related to the external sodium concentration.


1960 ◽  
Vol XXXIII (IV) ◽  
pp. 630-636
Author(s):  
F.-E. Krusius ◽  
P. Peltola

ABSTRACT The study reported here was performed in order to examine the tap water of Helsinki for its alleged goitrogenous effect. In a short-term, 24-hour experiment with rats, kept on an iodine-poor diet, we noticed no inhibition of the 4-hour 131I uptake, as compared with that of animals receiving physiological saline instead of tap water. Two similar groups of rats receiving 1 and 2 mg of mercazole in redistilled water showed a distinct blockage of the 4-hour uptake, which proved the effect of this substance. In a long-term experiment of 5 weeks' duration there was no detectable difference in the body weight, thyroid weight and the 4-hour 131I uptake when the rats receiving tap water or distilled water to which 0.45 per cent of sodium chloride was added were compared with each other. Replacement of tap water by a 10 mg per cent solution of mercazole in redistilled water enlarged the thyroid to double its normal weight and increased the 131I uptake to approximately five times that of the controls. Thus our experiments failed to demonstrate any goitrogenous effect in the tap water of Helsinki. Changes similar to those produced by a long-term administration of mercazole, i. e. an enlargement of the thyroid and an increased thyroidal iodine uptake, have been shown to be due to milk collected from goitrous areas. The observations here reported confirm the importance of milk in the genesis of the goitre endemia of Helsinki. Attention is further called to the fact that a thyroidal enlargement combined with an increased thyroidal iodine uptake cannot always be taken as a sign of iodine deficiency because similar changes may be produced by the administration of goitrogens.


Author(s):  
Nael Mohammed Sarheed ◽  
Osamah Faisal Kokas ◽  
Doaa Abd Alabas Muhammed Ridh

The plant of castor is widely spread in the Iraqi land, and characterized with containing ricin toxin, which has a very serious effects, and because the seeds of this plant scattered in the agricultural soil and rivers water, which increases the exposure of humans and animals to these beans. Objective: This experiment was designed to study the effect of high concentration of castor bean powder in some physiological and biochemical parameters and changes in some tissues of the body, as well as trying to use doxycycline to reduce the effects of ingestion of these seeds. Materials and Methods: In the experiment, 24 local rabbits were raised and fed in the Animal House of the Faculty of Medicine / Al-Muthanna University, then divided into four groups and treated for three weeks (21 days), Control group: treated with normal saline solution (0.9) orally throughout the experiment, G1: was treated orally with a concentration of 25 mg / kg of castor bean powder daily during the experiment, G2 : orally treated 25 mg / kg of castor bean and 25 mg / kg of doxycycline, G3: orally treated 25 mg / kg of castor powder with 50 mg / kg of doxycycline daily throughout the trial period. Results: The results of the experiment showed significant changes (P less than 0.05) in all physiological and biochemical blood tests when compared with control group. There was a significant decrease in PCV, Hb, RBC, T.protein and body weights, while demonstrated a significant increase in WBC, Urea, Creatinine, ALT, AST and ALP, with distortions in liver and kidney of animals that treated with Castor beans. In contrast, the treatment with doxycycline and caster beans showed significant improvement reflected by a normal proportion in physiological tests and biochemical tests with improvement in the tissues when compared to control group. Conclusions: It can be concluded from this study that castor bean has high toxic and pathogenic effects that may be dangerous to the life of the organism. Therefore, it is advisable to be cautious of these pills and avoid exposure to them, also recommended to take high concentrations of doxycycline treatment when infected with castor bean poisoning.


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