Renal responses to chronic cold exposure

2003 ◽  
Vol 81 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Zhongjie Sun ◽  
Zhonge Zhang ◽  
Robert Cade
Keyword(s):  
Food Intake ◽  
Cold Exposure ◽  
Water Loss ◽  
Urine Output ◽  
Room Temperature ◽  
Urine Osmolality ◽  
Urine Flow ◽  
Receptor Mrna ◽  
The Difference ◽  
Renal Responses

The aim of this study was to assess our hypothesis that the release of antidiuretic hormone (ADH), the renal concentrating response to ADH, or both is decreased by prolonged cold exposure. Six groups (n = 6/group) of rats were used. Three groups were exposed to cold (5°C), while the remaining three groups were kept at room temperature (25°C). It was found that urine osmolality decreased significantly and serum osmolality increased significantly during cold exposure. The ratio of water/food intake was not affected by prolonged cold exposure. However, prolonged cold exposure increased the ratio of urine output/food intake in the cold-exposed rats, indicating that more urine flow is required by the cold-exposed rats to excrete the osmotic substance at a given food intake. The difference between water intake and urine output decreased significantly in the cold-exposed rats. Thus, prolonged cold exposure increases water loss from excretion. Renal concentrating responses to 24-h dehydration and Pitressin were decreased significantly in the cold-exposed rats. Plasma ADH levels remained unchanged, but renal ADH receptor (V2 receptor) mRNA was decreased significantly in the cold-exposed rats. The results strongly support the conclusion that cold exposure increases excretive water loss, and this may be due to suppression of renal V2 receptors rather than inhibition of ADH release.Key words: renal concentrating response, cold-induced dehydration, serum and urine osmolality, ADH, renal V2 receptor mRNA.

Genetic AVP deficiency abolishes cold-induced diuresis but does not attenuate cold-induced hypertension

2006 ◽  
Vol 290 (6) ◽  
pp. F1472-F1477 ◽  
Author(s):  
Zhongjie Sun
Keyword(s):  
Cold Exposure ◽  
Urine Output ◽  
Room Temperature ◽  
Control Period ◽  
Free Water ◽  
Renal Medulla ◽  
Urine Osmolality ◽  
Free Water Clearance ◽  
Receptor Mrna ◽  
Induced Hypertension

Chronic cold exposure causes hypertension and diuresis. The aim of this study was to determine whether vasopressin (AVP) plays a role in cold-induced hypertension and diuresis. Two groups of Long-Evans (LE) and two groups of homozygous AVP-deficient Brattleboro (VD) rats were used. Blood pressure (BP) was not different among the four groups during a 2-wk control period at room temperature (25°C, warm). After the control period, one LE group and one VD group were exposed to cold (5°C); the remaining groups were kept at room temperature. BP and body weight were measured weekly during exposure to cold. Food intake, water intake, urine output, and urine osmolality were measured during weeks 1, 3, and 5 of cold exposure. At the end of week 5, all animals were killed and blood was collected for measurement of plasma AVP. Kidneys were removed for measurement of renal medulla V2 receptor mRNA and aquaporin-2 (AQP-2) protein expression. BP of LE and VD rats increased significantly by week 2 of cold exposure and reached a high level by week 5. BP elevations developed at approximately the same rate and to the same degree in LE and VD rats. AVP deficiency significantly increased urine output and solute-free water clearance and decreased urine osmolality. Chronic cold exposure increased urine output and solute-free water clearance and decreased urine osmolality in LE rats, indicating that cold exposure caused diuresis in LE rats. Cold exposure failed to affect these parameters in VD rats, suggesting that the AVP system is responsible for cold-induced diuresis. Cold exposure did not alter plasma AVP in LE rats. Renal medulla V2 receptor mRNA and AQP-2 protein expression levels were decreased significantly in the cold-exposed LE rats, suggesting that cold exposure inhibited renal V2 receptors and AVP-inducible AQP-2 water channels. We conclude that 1) AVP may not be involved in the pathogenesis of cold-induced hypertension, 2) the AVP system plays a critical role in cold-induced diuresis, and 3) cold-induced diuresis is due to suppression of renal V2 receptors and the associated AQP-2 water channels, rather than inhibition of AVP release.

Water and electrolyte exchange in rats exposed to cold

1968 ◽  
Vol 46 (6) ◽  
pp. 873-881 ◽  
Author(s):  
Melvin J. Fregly
Keyword(s):  
Food Intake ◽  
Water Intake ◽  
Cold Exposure ◽  
Urine Output ◽  
Plasma Osmolality ◽  
Urine Osmolality ◽  
Total Output ◽  
Electrolyte Loss ◽  
Sodium And Potassium ◽  
Electrolyte Exchange

Exposure of rats to air at 6 °C for 10 days increased food intake and urine output but failed to affect water intake. A comparison of water with food intake revealed a smaller water intake for a given food intake for cold-exposed than for control rats. The urine output at a given water intake was also greater for cold-exposed rats. In addition, cold exposure failed to affect urine osmolality significantly. Thus, the greater solute output accompanying cold exposure was accomplished by increasing urine flow rather than by concentrating urine. These results suggest possible mechanisms for both the relative dehydration and increased plasma osmolality observed after removal of rats from cold air. Both fecal and urinary routes of sodium and potassium excretion were increased by cold exposure; however, fecal excretions of both potassium and sodium were greater fractions of the total output during cold exposure than prior to it. Although cold exposure tends to induce a relative dehydration in rats, an important factor limiting the extent of the dehydration may be increased fecal electrolyte loss.

scholarly journals Effects of Room Temperature, Seasonal Condition and Food Intake on Finger Skin Temperature during Cold Exposure Test for Diagnosing Hand-Arm Vibration Syndrome.

1998 ◽  
Vol 36 (2) ◽  
pp. 166-170 ◽  
Author(s):  
Noriaki HARADA ◽  
Mieko IWAMOTO ◽  
Md Shawkatuzzaman LASKAR ◽  
Iwao HIROSAWA ◽  
Minoru NAKAMOTO ◽  
...  
Keyword(s):  
Food Intake ◽  
Skin Temperature ◽  
Cold Exposure ◽  
Room Temperature ◽  
Finger Skin Temperature ◽  
Vibration Syndrome ◽  
Exposure Test ◽  
Finger Skin

scholarly journals Flexibility in basal metabolic rate and evaporative water loss among hoopoe larks exposed to different environmental temperatures

2000 ◽  
Vol 203 (20) ◽  
pp. 3153-3159 ◽  
Author(s):  
J.B. Williams ◽  
B.I. Tieleman
Keyword(s):  
Food Intake ◽  
Metabolic Rate ◽  
Body Mass ◽  
Cold Exposure ◽  
Basal Metabolic Rate ◽  
Water Loss ◽  
Energy Demand ◽  
Exposure Group ◽  
Internal Organs ◽  
Evaporative Water

The ‘energy demand’ hypothesis for short-term adjustments in basal metabolic rate (BMR) posits that birds adjust the size of their internal organs relative to food intake, a correlate of energy demand. We tested this hypothesis on hoopoe larks (Alaemon alaudipes), inhabitants of the Arabian desert, by acclimating birds for 3 weeks at 15 degrees C and at 36 degrees C, then measuring their BMR and total evaporative water loss (TEWL). Thereafter, we determined the dry masses of their brain, heart, liver, kidney, stomach, intestine and muscles of the pectoral region. Although mean body mass did not differ initially between the two groups, after 3 weeks, birds in the 15 degrees C group had gained mass (44.1+/−6.5 g), whereas larks in the 36 degrees C group had maintained a constant mass (36.6+/−3.6 g; means +/− s.d., N=6). Birds in the 15 degrees C group had a mean BMR of 46.8+/−6.9 kJ day(−1), whereas birds in the 36 degrees C group had a BMR of 32.9+/−6.3 kJ day(−1), values that were significantly different when we controlled for differences in body mass. When measured at 35 degrees C, larks in the cold-exposure group had a TEWL of 3.55+/−0.60 g H(2)O day(−)(1), whereas TEWL for birds in the 36 degrees C group averaged 2.23+/−0.28 g H(2)O day(−1), a difference of 59.2%. Mass-independent TEWL differed significantly between groups. Larks in the 15 degrees C group had a significantly larger liver, kidney and intestine than larks in the 36 degrees C group. The total increase in organ mass contributed 14.3% towards the total mass increment in the cold exposure group. Increased food intake among larks in the cold group apparently resulted in enlargement of some of the internal organs, and the increase in mass of these organs required a higher rate of oxygen uptake to support them. As oxygen demands increased, larks apparently lost more evaporative water, but the relationship between increases in BMR and TEWL remains unresolved.

Eggs of spruce grouse dry at a faster rate than those of ruffed grouse

2006 ◽  
Vol 84 (11) ◽  
pp. 1688-1692 ◽  
Author(s):  
James F. Bendell ◽  
L.I. Bendell–Young
Keyword(s):  
Water Loss ◽  
Room Temperature ◽  
Distribution Density ◽  
Nest Site ◽  
Ruffed Grouse ◽  
Pore Density ◽  
Bonasa Umbellus ◽  
The Difference ◽  
Behavioural Aspects ◽  
Different Parts

We measured the rate of water loss and pore density of eggs of spruce grouse ( Canachites canadensis canace (L., 1766)) and ruffed grouse ( Bonasa umbellus togata (L., 1766)) from different parts of their range in Ontario. Eggs were dried in enclosed glass jars over Drierite® and in paper trays in open air at room temperature and humidity. Eggs were weighed to the nearest 0.01 g every 2–4 days and the change in mass was measured as water loss. Pores of shells were counted (pores/cm2) in the blunt, middle, and pointed sections of the egg. Eggs of spruce grouse lost water at a faster rate in Drierite® and in open air and had a greater density of pores than eggs of ruffed grouse. Rates of water loss were constant and varied inversely with ambient humidity, with the difference between species greatest in open air. Eggs late in incubation of ruffed grouse dried at a faster rate than those early in incubation in Drierite®. The adaptations of eggs of each grouse to the moisture of the nest may help explain their distribution, density, and habitat and nest-site selections, as well as behavioural aspects of the nesting hen. Both, especially the spruce grouse, may be good indictors of climate change.

Ovine fetal swallowing and renal responses to oligohydramnios

1994 ◽  
Vol 266 (3) ◽  
pp. R972-R978 ◽  
Author(s):  
L. K. Kullama ◽  
C. L. Agnew ◽  
L. Day ◽  
M. G. Ervin ◽  
M. G. Ross
Keyword(s):  
Amniotic Fluid ◽  
Volume Regulation ◽  
Urine Osmolality ◽  
Urine Flow ◽  
Fetal Urine ◽  
Chloride Excretion ◽  
Fluid Production ◽  
Ovine Fetus ◽  
Ovine Fetal ◽  
Renal Responses

Amniotic fluid (AF) volume regulation is dependent on a balance between fluid production and fluid resorption. We examined the effects of reduced AF volume on AF production by fetal urine and resorption by fetal swallowing and the response of these parameters to AF volume replacement. Eight time-dated pregnant ewes (125 +/- 1 days gestation) were studied before (day 1) and after (day 3) AF and fetal urine drainage. Drainage resulted in a significant decrease in AF volume (415 +/- 89 to 157 +/- 36 ml). Fetal urine osmolality increased (139 +/- 10 to 286 +/- 33 mosmol/kgH2O), while urine flow did not change significantly (0.31 +/- 0.04 to 0.23 +/- 0.06 ml/min), resulting in nonsignificant increases in osmolar, sodium, and chloride excretions. Fetal electromyographic swallowing activity decreased 30% (1.0 +/- 0.1 to 0.7 +/- 0.1 swallows/min; P < 0.05), while net esophageal flow decreased 74% (0.31 +/- 0.12 to 0.07 +/- 0.04 ml/min; P < 0.05). On day 4, 0.15 M NaCl (500 ml; 37 degrees C) was administered into the AF over 30 min. During the 2 h after reinfusion, urine flow (0.29 +/- 0.07 to 0.40 +/- 0.09 ml/min) and osmolar sodium and chloride excretion significantly increased, though fetal swallowing activity and esophageal flow did not change. Thus the ovine fetus responded to reduced AF volume by maintaining AF production and decreasing AF resorption. In response to AF replacement, urine flow increased while fetal swallowing activity did not change, consistent with an intramembranous pathway for fetal AF resorption.

V1- and V2-receptor contributions to ovine fetal renal and cardiovascular responses to vasopressin

1992 ◽  
Vol 262 (4) ◽  
pp. R636-R643
Author(s):  
M. G. Ervin ◽  
M. G. Ross ◽  
R. D. Leake ◽  
D. A. Fisher
Keyword(s):  
Receptor Agonist ◽  
Urine Osmolality ◽  
Cardiovascular Responses ◽  
Urine Flow ◽  
Receptor Blockade ◽  
Fetal Life ◽  
Receptor Stimulation ◽  
V2 Receptor ◽  
Ovine Fetal ◽  
Renal Responses

To assess the contributions of arginine vasopressin (AVP) V1- and V2-receptors to the ovine fetal responses to AVP, we studied V2-receptor stimulation in the presence of V1-receptor blockade, and selective V2-receptor stimulation in chronically catheterized fetal lambs. AVP administration (20 ng/kg) to the saline infused fetuses (n = 8; 132 +/- 2 days) significantly increased mean arterial pressure (MAP; 45 +/- 2 to 53 +/- 4 mmHg) and urine osmolality (Uosm; 134 +/- 13 to 379 +/- 42 mosmol/kgH2O) and decreased heart rate (HR; 168 +/- 3 to 147 +/- 5 beats/min) and urine flow (V; 0.48 +/- 0.10 to 0.19 +/- 0.03 ml/min). V1-receptor antagonist infusion, [d(CH2)5,Tyr(Me)]AVP (n = 7; 134 +/- 1 days) had no effect on fetal MAP, Uosm, HR, or V. V1-receptor blockade abolished the MAP response to AVP without affecting the HR and urinary responses. In a second series of animals (n = 6; 131 +/- 1 days), selective V2-receptor agonist infusion [desmopressin (DDAVP)] had no effect on fetal MAP or HR while initial changes in V and Uosm were identical to the effects of AVP alone. Our results demonstrate clear discrimination of V1- and V2-receptor-mediated events in the fetal MAP and renal responses to AVP. Moreover, the HR response to AVP is not mediated by the population of V1-receptors blocked by [d(CH2)5,Tyr(Me)]AVP or V2-receptors stimulated by DDAVP, suggesting the presence of additional AVP receptor subclass(es) during fetal life.

EFFECTS OF ARGININE-, LYSINE- AND LEUCINE-VASOPRESSIN ON URINARY OSMOLALITY AND RATE OF URINE FLOW IN HYDRATED RATS AND DOGS

1959 ◽  
Vol XXXII (I) ◽  
pp. 134-141 ◽  
Author(s):  
Niels A. Thorn
Keyword(s):  
Arginine Vasopressin ◽  
Urine Osmolality ◽  
Urine Flow ◽  
The Other ◽  
Maximum Increase ◽  
Urinary Osmolality ◽  
Lysine Vasopressin

ABSTRACT Arginine-, lysine- and leucine-vasopressin, injected i. v. into hydrated rats or dogs caused different patterns of response in that urine osmolality fell much more slowly after the maximum increase following arginine-vasopressin, than after the other two preparations. Using 3 different parameters for antidiuretic response, arginine-vasopressin was somewhat more potent than leucine-vasopressin in both rats and dogs, considerably more potent than lysine-vasopressin in rats, and much more so in dogs.

ADAPTATION OF WHITE MICE (MUS MUSCULUS) TO REPEATED COOLING

1967 ◽  
Vol 45 (3) ◽  
pp. 321-327 ◽  
Author(s):  
David M. Ogilvie
Keyword(s):  
Body Temperature ◽  
Rectal Temperature ◽  
Cold Exposure ◽  
Mus Musculus ◽  
Room Temperature ◽  
The Body ◽  
Progressive Decrease

The effects, on the body temperature of white mice, of repeated short exposures to cold were investigated using two methods of restraint. Animals held in a flattened posture became hypothermic at room temperature, cooled more than five times as fast at −10 °C as mice that could adopt a heat-conserving posture, and continued to cool for some time after they were removed from the cold. With repeated tests, cooling at room temperature decreased, and an improvement in re warming ability was observed. In addition, with lightly restrained mice, the fall in rectal temperature during cold exposure showed a progressive decrease, a phenomenon not observed with severely restrained animals.

scholarly journals Open-loop analysis on sympathetically mediated arterial pressure and urine output responses in spontaneously hypertensive rats: effect of renal denervation

2021 ◽  
Vol 71 (1) ◽  
Author(s):  
Toru Kawada ◽  
Takuya Nishikawa ◽  
Satoru Suehara ◽  
Satoshi Sawada ◽  
Tetsuo Tanaka ◽  
...  
Keyword(s):  
Arterial Pressure ◽  
Urine Output ◽  
Spontaneously Hypertensive Rats ◽  
Renal Denervation ◽  
Sympathetic Innervation ◽  
Urine Flow ◽  
Hypertensive Rats ◽  
Loop Analysis ◽  
Intact Side ◽  
Spontaneously Hypertensive

AbstractPrimary acute sympathetic activation (PASA) causes a subsequent arterial pressure (AP) elevation. In this case, an antidiuretic effect via the renal innervation and pressure diuresis can act antagonistically on the kidneys. We examined the effect of PASA on urine output in spontaneously hypertensive rats (SHR) 4–7 days after unilateral renal denervation (RDN) (n = 9). The slope of the plot of urine flow versus AP was positive (0.120 ± 0.031 μL min−1 kg−1 mmHg−1) on the intact side, but it was less than 1/3 of the slope observed previously in normotensive Wistar–Kyoto rats (WKY). RDN did not normalize the slope of urine flow versus AP (0.179 ± 0.025 μL min−1 kg−1 mmHg−1, P = 0.098 versus the intact side). The urine flow at the operating point of the AP tended to be greater on the denervated than the intact side (29.0 ± 1.8 vs. 25.3 ± 1.9 μL min−1 kg−1, P = 0.055). The percent increase (17.2 ± 7.2%) was not different from that observed previously in WKY. Although high-resting sympathetic nerve activity is prerequisite for maintaining hypertension in SHR, the effect of sympathetic innervation on the urine output function was not greater than that in WKY.

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