A contribution to the studies on changes of energy metabolism during postnatal development. I. Development of mechanisms of body temperature regulation in rats

Poczopko, P

doi:10.1002/jcp.1030570305

Cited by 25 publications

(10 citation statements)

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“…It is not at all an exceptional case. Lower body temperature in relation to adult animals was found in young rats (Hill, 1947;Poczopko, 1961), chicken (Randall, 1943) and goslings (Poczopko, 1967). The normal body temperature in rats is achieved within one month similarly to baby rabbits whereas in chicken it takes 20 days and in gosling 5 days.…”

Section: Changes Of the Body And Skin Temperatures During Cooling Andmentioning

confidence: 99%

“…The regulation of heat losses from the body surface may occur only by vasomotor changes of blood circulation in the skin. In new-born rats the mechanism of vasomotor regulation of heat losses is not developed (Taylor, 1960;Poczopko, 1961) but in baby rabbits the situation is different. Already in 2-day-old rabbits, and perhaps in younger as well, the difference between skin and rectal temperatures is more pronounced in cold than in warm surroundings (Table 2).…”

Section: Changes Of the Body And Skin Temperatures During Cooling Andmentioning

confidence: 99%

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The Development of resistance to cooling in baby rabbits

Poczopko¹

1969

Acta Theriol.

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The studies were carried out on baby rabbits born in autumn or spring in cages kept in an open shed. The air temperautre in the shed varied from 2 to 25°C but the nest temperature was almost independent of these changes and in the coldest part of nest amounted to 20-26°C. The normal body temperature of baby rabbits 1 hr after birth was equal to 34.2°C. During the first day it rose to approximately 37°C but then the increase was more slow and after 1 month it reached the normal temperature of adult rabbits (39.6°C). New-born rabbits kept separately are not able to maintain a constant body temperature even at relatively high ambient temperatures. The resistance to cooling, however, develops rather quickly. In 20°C 6-day-old rabbits retain constant body temperature and in 8°C 12-day-old specimens. The rate of body cooling of baby rabbits exposed to cold decreases with the age and this decrease is faster than the reduction of the relative body surface area (cm 2 /g). The increase of resistance to cooling in baby rabbits during first 8 days after birth may be partly explained by the improvement in the mechanism of vasomotor regulation of the heat losses and probably also by the augmented rate of heat production. From the eighth day after birth the hair cover plays more important role in thermal economy of baby rabbits.

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Section: Changes Of the Body And Skin Temperatures During Cooling Andmentioning

confidence: 99%

Section: Changes Of the Body And Skin Temperatures During Cooling Andmentioning

confidence: 99%

The Development of resistance to cooling in baby rabbits

Poczopko¹

1969

Acta Theriol.

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“…Lagerspetz, 1962) or the rat (G u 1 i c k, 1937; Buchanan & Hill, 1947;Poczopko, 1961) differ only slightly from poikilothermic animals. When comparing the capacity for maintaining thermal homeostasis in newborn rats and calves it is, however, difficult to understand clearly the causes of these differences, since they may to a considerable extent be due to the less favourable body surface to body mass ratio in the rat, and not only to the immaturity of thermoregulation mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Changes in thermogenesis and its hormonal regulators during the postnatal development of rabbits and guinea pigs

Piekarzewska¹

1977

Acta Theriol.

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“…When in the nest, however, young mice and rats are able to maintain their body temperature (Tb) within a relatively narrow range of about 33°-37°C, even though Ta may be much lower, depending upon a combination of factors, including heat production, infant huddling, insulation quality of the nest, and maternal behaviors (see Leon, 1986, for a review). During the first 3 weeks of life, pups develop an increasing ability to maintain nest-level Teo when isolated at increasingly lower Tas (see, e.g., Conklin & Heggeness, 1971;Fairfield, 1948;Poczopko, 1961). The transition from a poikilothermic to a homeothermic state is not simple, and it clearly reflects the increasing ability of the infant to maintain a thermal balance between heat production and heat loss, using either physiological or behavioral means.…”

mentioning

confidence: 99%

“…If Ta is very low, the pup may not be able to reach an area of higher temperature, resulting in further heat loss, with subsequent hypothermic immobility, additional heat loss, and, eventually, death. Although vascular response to lowered Ta has been suggested as early as 4 days of age (Poczopko, 1961), most researchers have found little evidence of this ability until 12-14 days of age in the rat (e.g., Conklin et al, 1971;Taylor, 1960). Furthermore, because most mice and rats are born without fur, they lack both passive (insulation provided by fur) and active (piloerection) means of reducing the rate of heat loss that are available to the adult.…”

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Development of homeothermy in infant C3H mice

Nagy

1993

Bull. Psychon. Soc.

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The ability ofC3H mice to maintain normal nest-level body temperatures when removed from the nest and isolated at room temperature (24°C) was examined between 2 and 30 days of age. To account for the increasing body size and fur growth which might serve to decrease the rates of heat loss in the developing mouse, colonic temperatures were recorded for isolated live and dead mice matched for age, body weight, and pelage, over a 1-h exposure to 24°C. The results point to there being three stages of thermoregulatory development: 2-5, 8-15, and 18-30 days of age, with the pup being unable to maintain normal body temperature when isolated from the nest until 18 days of age. Increases in body size, weight, and growth of fur had little effect on heat loss through 18 days of age.It is well known that the newborn of certain altricial mammals, including the common house mouse (Mus musculus) and the Norway rat (Ranus norvegicus), lack adultlike thermoregulatory capabilities and have been regarded as essentially poikilothermic (see, e.g., Adolph, 1957;Fairfield, 1948;Lagerspetz, 1962;Pichotka, 1971). When removed from the nest and isolated at an ambient temperature (Ta) lower than nest-temperature (Tn), the colonic temperature (Teo) of newborn pups drops quickly to levels only slightly above Ta. When in the nest, however, young mice and rats are able to maintain their body temperature (Tb) within a relatively narrow range of about 33°-37°C, even though Ta may be much lower, depending upon a combination of factors, including heat production, infant huddling, insulation quality of the nest, and maternal behaviors (see Leon, 1986, for a review). During the first 3 weeks of life, pups develop an increasing ability to maintain nest-level Teo when isolated at increasingly lower Tas (see, e.g., Conklin & Heggeness, 1971;Fairfield, 1948;Poczopko, 1961). The transition from a poikilothermic to a homeothermic state is not simple, and it clearly reflects the increasing ability of the infant to maintain a thermal balance between heat production and heat loss, using either physiological or behavioral means.In adult mice and rats, exposure to a Ta below the zone of thermal neutrality results in a sequence of behavioral and/or physiological responses in order to increase Tb. The initial attempt is usually behavioral, consisting simply of moving to an area of higher Ta. If unsuccessful, adults may attempt next to conserve heat loss by means of general vasoconstriction of peripheral blood vessels and/or piloerection of fur. With further decreases in adult Tb, oxygen (02) consumption increases and there is an increase in heat production by both shivering and nonshivering mechanisms (see Bligh, 1973, for a review).

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A contribution to the studies on changes of energy metabolism during postnatal development. I. Development of mechanisms of body temperature regulation in rats

Cited by 25 publications

References 11 publications

The Development of resistance to cooling in baby rabbits

The Development of resistance to cooling in baby rabbits

Changes in thermogenesis and its hormonal regulators during the postnatal development of rabbits and guinea pigs

Development of homeothermy in infant C3H mice

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