Blood viscosity and hematocrit in the estuarine crocodile, Crocodylus porosus

Wells, R. M. G.; Beard, Laura; Grigg, Gordon C.

doi:10.1016/0300-9629(91)90025-8

Cited by 9 publications

(8 citation statements)

References 29 publications

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“…However, little was known about longterm effects of prolonged exposure to hyperosmotic environments on the maintenance of osmotic homeostasis. All haematological values measured in this study for SW-acclimated animals were within the ranges reported for wild-caught C. porosus living in water bodies of varying salinities (Grigg, 1981;Wells et al, 1991), suggesting that SW-acclimated crocodiles were able to successfully maintain osmotic homeostasis despite extended exposure to hyperosmotic conditions. Moreover, extended exposure to hypersaline conditions appeared to have little long-term impact on the animal's growth, suggesting that the additional energy required in maintaining homeostasis was either relatively minimal or was compensated for by increased food intake (animals were fed ad libitum, so we cannot readily distinguish between these possibilities).…”

Section: Discussionsupporting

confidence: 75%

Functional and morphological plasticity of crocodile (Crocodylus porosus) salt glands

Cramp

Meyer

Sparks

et al. 2008

Journal of Experimental Biology

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SUMMARYThe estuarine crocodile, Crocodylus porosus, inhabits both freshwater and hypersaline waterways and maintains ionic homeostasis by excreting excess sodium and chloride ions via lingual salt glands. In the present study, we sought to investigate the phenotypic plasticity, both morphological and functional, in the lingual salt glands of the estuarine crocodile associated with chronic exposure to freshwater (FW) and saltwater (SW) environments. Examination of haematological parameters indicated that there were no long-term disruptions to ionic homeostasis with prolonged exposure to SW. Maximal secretory rates from the salt glands of SW-acclimated animals (100.8±14.7·mol·100·g ). There were no differences in the mass-specific metabolic rate of salt gland tissue slices from FW-and SW-acclimated animals (558.9±49.6 and 527.3±142.8·l·O 2 ·g -1 ·h -1 , respectively). Stimulation of the tissue slices from SW-acclimated animals by methacholine resulted in a 33% increase in oxygen consumption rate. There was no significant increase in the metabolic rate of tissues from FW-acclimated animals in response to methacholine. Morphologically, the secretory cells from the salt glands of SW-acclimated animals were larger than those of FW-acclimated animals. In addition, there were significantly more mitochondria per unit volume in secretory tissue from SW-acclimated animals. The results from this study demonstrate that the salt glands of C. porosus are phenotypically plastic, both morphologically and functionally and acclimate to changes in environmental salinity.

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Section: Discussionsupporting

confidence: 75%

Functional and morphological plasticity of crocodile (Crocodylus porosus) salt glands

Cramp

Meyer

Sparks

et al. 2008

Journal of Experimental Biology

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“…Insect hemocytes may respond similarly to decreases in temperature, potentially explaining the steep incline in viscosity at low temperatures observed in the hemolymph of M. sexta larvae. The whole hemolymph viscosity values found here, irrespective of temperature, are similar in magnitude to values reported in other animals (Clarke and Nicol, 1993;Dunlap, 2006;Guard and Murrish, 1975;Macdonald and Wells, 1991;Palenske and Saunders, 2002;Wells et al, 1991). In most cases, direct comparisons cannot be made, because measurements have been conducted at different shear rates and temperature.…”

Section: Discussionsupporting

confidence: 60%

“…In most cases, direct comparisons cannot be made, because measurements have been conducted at different shear rates and temperature. When compared with the few viscosity measurements that have been made at the same shear rate (450 s −1 ) and temperature (30°C), the insect hemolymph viscosity (range=2.1-2.7 cP) is found to be close to that of both crocodiles (average=2.89 cP; Wells et al, 1991) and the western fence lizard (range=2.7-5.9 cP, with higher values at greater hematocrit; Dunlap, 2006). The differences are likely due to the percentage of cell mass within the blood, which is directly correlated with blood viscosity across species (Snyder, 1971;Woodcock, 1976).…”

Section: Discussionmentioning

confidence: 88%

“…The differences are likely due to the percentage of cell mass within the blood, which is directly correlated with blood viscosity across species (Snyder, 1971;Woodcock, 1976). The hematocrit percent of insect hemolymph is <5% (Clark and Jones, 1980), which is considerably less than the 18.7-50.8% measured in crocodiles and the western fence lizard (Dunlap, 2006;Wells et al, 1991). The removal of cell mass from blood to obtain plasma yields a lower viscosity in many organisms (Windberger et al, 2003), as is also seen here with insect whole hemolymph compared with plasma.…”

Section: Discussionmentioning

confidence: 96%

“…These physical properties include viscosity and density, which are biologically important because they directly influence the energetic requirements of flow production and patterns of flow throughout the body within an open circulatory system (Vogel, 1993(Vogel, , 1994. Blood viscosity has been measured in many vertebrates, including mammals (Amin and Sirs, 1985;Windberger et al, 2003), fish (Brill and Jones, 1994;Macdonald and Wells, 1991;Wells and Baldwin, 1990), reptiles (Dunlap, 2006;Snyder, 1971;Wells et al, 1991), amphibians (Palenske and Saunders, 2003) and birds (Clarke and Nicol, 1993;Zhou et al, 1999). However, perhaps owing to the presence of an open system, blood viscosity is generally unstudied in invertebrates (Snyder, 1978) and is unknown in insects.…”

Section: Introductionmentioning

confidence: 99%

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How temperature influences the viscosity of hornworm hemolymph

Kenny

Giarra

Granata³

et al. 2018

Journal of Experimental Biology

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Hemolymph is responsible for the transport of nutrients and metabolic waste within the insect circulatory system. Circulation of hemolymph is governed by viscosity, a physical property, which is well known to be influenced by temperature. However, the effect of temperature on hemolymph viscosity is unknown. We used larvae to measure hemolymph viscosity across a range of physiologically relevant temperatures. Measurements were taken from 0 to 45°C using a cone and plate viscometer in a sealed environmental chamber. Hemolymph viscosity decreased with increasing temperature, showing a 6.4-fold change (11.08 to 1.74 cP) across the temperature range. Viscosity values exhibited two behaviors, changing rapidly from 0 to 15°C and slowly from 17.5 to 45°C. To test the effects of large particulates (e.g. cells) on viscosity, we also tested hemolymph plasma alone. Plasma viscosity also decreased as temperature increased, but did not exhibit two slope regimes, suggesting that particulates strongly influence low-temperature shifts in viscosity values. These results suggest that as environmental temperatures decrease, insects experience dramatic changes in hemolymph viscosity, leading to altered circulatory flows or increased energetic input to maintain similar flows. Such physical effects represent a previously unrecognized factor in the thermal biology of insects.

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Hemorheology and oxygen transport in vertebrates. A role in thermoregulation?

Viscor

Torrella

Fouces

et al. 2003

J. Physiol. Biochem.

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We studied the effect of temperature on blood rheology in three vertebrate species with different thermoregulation and erythrocyte characteristics. Higher fibrinogen proportion to total plasma protein was found in turtles (20%) than in pigeons (5.6%) and rats (4.2%). Higher plasma viscosity at room temperature than at homeotherm body temperature was observed in rats (1.69 mPa x s at 20 degrees C vs. 1.33 mPa x s at 37 degrees C), pigeons (3.40 mPa x s at 20 degrees C vs. 1.75 mPa x s at 40 degrees C), and turtles (1.74 mPa x s at 20 degrees C vs. 1.32 mPa x s at 37 degrees C). This fact allow us to hypothesize that thermal changes in protein structure may account for an adjustment of the plasma viscosity. Blood viscosity was dependent on shear rate, temperature and hematocrit in the three species. A different behaviour in apparent and relative viscosities between rat and pigeon at environmental temperature was found. Moreover, the blood oxygen transport capacity seems more affected by a reduction of temperature in rats than in pigeons. Both findings indicate a greater influence of temperature on mammalian erythrocyte than on nucleated red cells, possibly as a consequence of differences in thermal sensitivity and mechanical stability between them. A comparison between the three species revealed that apparent blood viscosity measured at homeotherm physiological temperature was linearly related to the hematocrit level of each species. However, when measured at environmental temperature, rat blood showed a higher apparent viscosity than those found in species with non-nucleated red cells, thus indicating a higher impact of temperature decrease on blood viscosity in mammals. This suggest that regional hypothermia caused by cold exposure may affect mammalian blood rheological behaviour in a higher extent than in other vertebrate species having nucleated red cells and, consequently, influencing circulatory function and oxygen transport.

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Blood viscosity and hematocrit in the estuarine crocodile, Crocodylus porosus

Cited by 9 publications

References 29 publications

Functional and morphological plasticity of crocodile (Crocodylus porosus) salt glands

Functional and morphological plasticity of crocodile (Crocodylus porosus) salt glands

How temperature influences the viscosity of hornworm hemolymph

Hemorheology and oxygen transport in vertebrates. A role in thermoregulation?

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