The role of the liver in the cutaneous respiratory compensation of the frog <i>(Rana esculenta)</i>

Frangioni, Giuliano; Borgioli, Gianfranco

doi:10.1111/j.1469-7998.1993.tb02700.x

Cited by 10 publications

(7 citation statements)

References 18 publications

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“…However, amphibians are provided with a compensatory mechanism which adapts their blood compartment to the respiratory conditions. This has been demonstrated in the crested newt (Frangioni & Borgioli, 1989, 1991a and the edible frog (Frangioni & Borgioli, 1993b): in well-oxygenated environments these animals hoard all the red blood cells (hereafter abbreviated as RBC) in excess of their oxygen demands in capacious storage sites (the newt spleen and the frog liver). When oxygen is insufficient, the hoarded RBC are poured back into the blood stream; up to 50 of their total mass of erythrocytes can be involved in this process, and thus both erythrocyte concentration In the blood (Frangioni & Borgioli, 1991a, b, 1993b and the volume of the hematic compartment (Frangioni & Borgioli, 1993a) oscillate greatly.…”

Section: Introductionmentioning

confidence: 99%

Hematological changes in the newt during the process of splenic decongestion in reply to hypoxia

Frangioni

Borgioli

1993

Bolletino di zoologia

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Specimens of the newt, Triturus cristatus carnifex (Laurenti), anesthetized with chlorobutanol and exposed to humid air at 6° C for 300 min, accumulate about 50 of their red blood cells (RBC) in the spleen. When the newts are transferred to still water at 18° C, the spleen releases the RBC back into circulation, emptying itself out completely. This process counteracts the hypoxia caused by both the increase in temperature and low coefficient of oxygen diffusion in water. The analysis of the RBC counts, hematocrit value and percentage volumes of the spleen, blood and plasma (the last measured colorimetrically after injecting 0.05 ml of Evans blue in the conus arteriosus) in groups of newts sampled at various periods during the spleen decongestion reveals the trend of the compensatory process. The emptying out of the spleen takes less than an hour, causing significant increases in the RBC concentration after 15 and 30 min of immersion; the counts then undergo an inflexion which becomes significant at 120 min. The release of RBC into the blood stream causes an increase in blood volume which becomes statistically significant after 60 min, but reaches the value of the whole mass of the transferred RBC only after 120 min. The transfer of plasma during the compensatory process is the reason why the increases in RBC hematic concentration and in blood volume are not contemporary, as demonstrated by the significant decrease in plasma volume during spleen decongestion and by its increase (correlated to the decrease in RBC concentration) during the successive phases.

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Section: Introductionmentioning

confidence: 99%

Hematological changes in the newt during the process of splenic decongestion in reply to hypoxia

Frangioni

Borgioli

1993

Bolletino di zoologia

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“…Two forms have been identified which utilize the liver rather than the spleen as a 'storehouse' in the compensatory mechanism: Rana esculenta (Frangioni & Borgioli, 1993d, 1994 and the phreatobic cyprinid Phreatichthys andruzzii (Frangioni et al, unpublished). The intervention of the hematic compartment in controlling respiration seems a requisite of ectotherms, of fundamental importance, from the physiological point of view, for rapidly conforming the oxygen supply to the metabolic demands.…”

Section: Discussionmentioning

confidence: 99%

Blood and splenic respiratory compensation in larval newts

Borgioli¹,

Frangioni²

1997

Italian Journal of Zoology

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In Triturus carnifex, the mechanism of respiratory compensation which regulates the quantity of circulating erythrocytes according to the environmental conditions is already active in larvae at Glücksohn's stage LXI. Larvae anesthetized with chlorbutol and kept at 27° C for 25 min show red blood cell (RBC) counts slightly below 70 000/mm 3 and hematocrit values around 17, while those kept at 6° C for 100 min -the time necessary for the heart to beat the same number of times as at the former temperature -show significantly lower values (P < 0.01): about 40 000 RBC/mm 3 and a hematocrit of 11. The percentage mass and histology of the spleens removed from specimens frozen in liquid nitrogen immediately after testing show that this organ is the site where excess erythrocytes are stored. Tests at 18° C show that, though the voluntary movements of the anesthetized larvae are completely blocked, their gills still move rhythmically, which prevents them from going into hypoxia in stagnant water as, instead, occurs in adults.

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“…Thus, newt hematic parameters vary notably according to the environmental and/or physiological conditions, in contrast to homeotherms in which such parameters remain normally constant (Farrell, 1991). This phenomenon is particularly significant because it is not limited to a particular form of life; the common edible frog (Rana esculenta) also possesses a respiratory compensation mechanism which produces analogous effects on the blood stream, with the difference that the organ which hoards the erythrocytes is the liver instead of the spleen (Frangioni & Borgioli, 1993b, 1994. It has been theorized that this type of compensatory phenomenon may be common among all amphibians (Frangioni & Borgioli, 1994), and perhaps among all ectothermal vertebrates (Frangioni, Berti & Borgioli, unpublished).…”

Section: Introductionmentioning

confidence: 99%

Variations in the blood pressure of newts according to their respiratory conditions

Frangioni

Borgioli

1996

Italian Journal of Zoology

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The newt Triturus carnifex is endowed with a mechanism of respiratory compensation which allows the animal to hoard erythrocytes in its spleen and release often large quantities of these into the blood stream, a factor which causes notable variations in all the hematological parameters according to variations in the environmental conditions. The mean arterial pressure, measured at the level of the right aortic arch with a Statham P23 XL transducer, also showed notable variations (from a minimum of about 11 cm to a maximum of about 30 cm of H 2 O). A statistical analysis of these pressure variations showed a positive correlation to blood volume and negative correlation to spleen volume in groups of 8 chlorbutolanaesthetized animals kept at 6°, 12° or 18° C with all their body surface exposed to the air (optimal respiratory condition). In identical groups of animals kept in stagnant water (hypozia-inducing condition), at the same three temperatures, the spleens appeared empty, and both blood volume and pressure showed constant values, intermediate to those of the animals exposed to the air. Thus, the depletion of the spleen in hypoxia is not due to an increase in pressure; however, this factor seems to control the maximum degree of congestion that the spleen can reach in optimal respiratory conditions.

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The role of the liver in the cutaneous respiratory compensation of the frog (Rana esculenta)

Cited by 10 publications

References 18 publications

Hematological changes in the newt during the process of splenic decongestion in reply to hypoxia

Hematological changes in the newt during the process of splenic decongestion in reply to hypoxia

Blood and splenic respiratory compensation in larval newts

Variations in the blood pressure of newts according to their respiratory conditions

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