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. 1972 Feb;220(3):511–528. doi: 10.1113/jphysiol.1972.sp009720

Regional distribution of cardiac output in young lambs: effect of cold exposure and treatment with catecholamines

G Alexander, A W Bell, B P Setchell
PMCID: PMC1331667  PMID: 5016035

Abstract

1. Lambs less than 3 days old, exposed to thermoneutral or intensely cold conditions in a respiration chamber, were infused with adrenaline or noradrenaline, 1 or 10 μg/kg.min; and the effects on oxygen consumption, cardiac output and its distribution to skin, skeletal and cardiac muscle, liver, spleen, kidney, gut, brown adipose tissue and brain were determined. Cardiac output was estimated by the Fick and dye dilution methods and the distribution of cardiac output by Sapirstein's method of fractional distribution of indicators.

2. Under thermoneutral conditions, metabolic rate was stimulated by both doses of noradrenaline and by the low, but not the high dose of adrenaline. Under cold conditions, the low dose of catecholamines had little effect on the already elevated metabolic rate, but the high doses depressed the metabolic response to cold.

3. The low dose of adrenaline increased cardiac output under thermoneutral conditions whereas the high dose decreased cardiac output; the effects of noradrenaline were less marked, in contrast to reported effects in new-born rabbits. The low doses of catecholamine given under cold conditions had little effect on the already elevated cardiac output, but the high doses, particularly of adrenaline, decreased cardiac output.

4. Blood flow through the skin of the extremities was markedly reduced by cold exposure, while flow through the peri-renal fat was doubled, flow through the skeletal muscle was quadrupled and flow through the cardiac muscle was trebled. These increases, particularly in skeletal muscle, were due to increased cardiac output and to vasodilation, as indicated by the reduced ratio of blood pressure to blood flow. Results are contrasted with published reports that blood flow through brown fat in new-born rabbits was greatly increased by cold, but muscle flow was scarcely altered.

5. In almost all organs examined the high doses of adrenaline infused in either environment markedly reduced blood flow, presumably by generalized vasoconstriction. Changes due to noradrenaline were small under thermoneutral conditions and flow through brown fat was increased by only 60% during infusion of 10 μg/kg.min. Much greater increases have been reported in new-born rabbits. Under cold conditions the high doses of noradrenaline tended to decrease flow in most organs including brown fat and muscle.

6. The results provide likely explanations for published reports that adrenaline failed to stimulate non-shivering thermogenesis or suppressed the mobilization of metabolites and the metabolic response to cold.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Alexander G., Mills S. C. Free fatty acids and glucose in the plasma of newly born lambs: effects of environmental temperature. Biol Neonat. 1968;13(1):53–61. doi: 10.1159/000240132. [DOI] [PubMed] [Google Scholar]
  2. Alexander G. The effect of adrenaline and noradrenaline on metabolic rate in young lambs. Biol Neonat. 1969;14(1):97–106. doi: 10.1159/000240175. [DOI] [PubMed] [Google Scholar]
  3. Alexander G., Williams D. Cardiovascular function in young lambs during summit metabolism. J Physiol. 1970 May;208(1):65–83. doi: 10.1113/jphysiol.1970.sp009106. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Alexander G., Williams D. Shivering and non-shivering therogenesis during summit metabolism in young lambs. J Physiol. 1968 Sep;198(2):251–276. doi: 10.1113/jphysiol.1968.sp008605. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Chatwin A. L., Linzell J. L., Setchell B. P. Cardiovascular changes during lactation in the rat. J Endocrinol. 1969 Jun;44(2):247–254. doi: 10.1677/joe.0.0440247. [DOI] [PubMed] [Google Scholar]
  6. DAWES G. S., MESTYAN G. CHANGES IN THE OXYGEN CONSUMPTION OF NEW-BORN GUINEA-PIGS AND RABBITS ON EXPOSURE TO COLD. J Physiol. 1963 Aug;168:22–42. doi: 10.1113/jphysiol.1963.sp007176. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. HULL D. OXYGEN CONSUMPTION AND BODY TEMPERATURE OF NEW-BORN RABBITS AND KITTENS EXPOSED TO COLD. J Physiol. 1965 Mar;177:192–202. doi: 10.1113/jphysiol.1965.sp007585. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Heim T., Hull D. The blood flow and oxygen consumption of brown adipose tissue in the new-born rabbit. J Physiol. 1966 Sep;186(1):42–55. doi: 10.1113/jphysiol.1966.sp008019. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Hull D. The structure and function of brown adipose tissue. Br Med Bull. 1966 Jan;22(1):92–96. doi: 10.1093/oxfordjournals.bmb.a070447. [DOI] [PubMed] [Google Scholar]
  10. Jansky L., Hart J. S. Cardiac output and organ blood flow in warm- and cold-acclimated rats exposed to cold. Can J Physiol Pharmacol. 1968 Jul;46(4):653–659. doi: 10.1139/y68-096. [DOI] [PubMed] [Google Scholar]
  11. Jenkinson D. M., Noble R. C., Thompson G. E. Adipose tissue and heat production in the new-born ox (Bos taurus). J Physiol. 1968 Apr;195(3):639–646. doi: 10.1113/jphysiol.1968.sp008479. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Járai I. The redistribution of cardiac output on cold exposure in new-born rabbits. J Physiol. 1969 Jun;202(3):559–567. doi: 10.1113/jphysiol.1969.sp008827. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Kuroshima A., Kono N., Ito S. Increase in the blood flow through brown adipose tissue in response to cold exposure and norepinephrine in the rat. Jpn J Physiol. 1967 Oct 15;17(5):523–537. doi: 10.2170/jjphysiol.17.523. [DOI] [PubMed] [Google Scholar]
  14. LeBlanc J., Mount L. E. Effects of noradrenaline and adrenaline on oxygen consumption rate and arterial blood pressure in the newborn pig. Nature. 1968 Jan 6;217(5123):77–78. doi: 10.1038/217077a0. [DOI] [PubMed] [Google Scholar]
  15. SAPIRSTEIN L. A. Regional blood flow by fractional distribution of indicators. Am J Physiol. 1958 Apr;193(1):161–168. doi: 10.1152/ajplegacy.1958.193.1.161. [DOI] [PubMed] [Google Scholar]
  16. SCOPES J. W., TIZARD J. P. The effect of intravenous noradrenaline on the oxygen consumption of new-born mammals. J Physiol. 1963 Feb;165:305–326. doi: 10.1113/jphysiol.1963.sp007058. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. VEREL D., SAYNOR R., KESTEVEN A. B. A spectrophotometric method of estimating blood oxygen using the unicam SP 600. J Clin Pathol. 1960 Jul;13:361–363. doi: 10.1136/jcp.13.4.361. [DOI] [PMC free article] [PubMed] [Google Scholar]

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