Summary
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1.
Five clipped sheep with spinal thermodes, exposed to an air temperature of 20°C, had a resting oxygen consumption\((\dot V{\text{O}}_{\text{2}} )\) of 5.9 ml/kg body weight · minute and a respiratory quotient (RQ) of 0.87. Cooling the spinal cord for 15 min from a mean temperature of 38.6°C down to 34.8°C caused\(\dot V{\text{O}}_{\text{2}} \) to rise to 7.6 ml/kg · min (P<0.02) and RQ to fall to 0.83 (P<0.001). More intense cooling of the spinal cord to 32.6°C caused\(\dot V{\text{O}}_{\text{2}} \) to increase to 9.6 ml/kg · min (P<0.01) while RQ fell to 0.80 (P<0.01). During spinal cooling the animals shivered. During the more intense spinal cooling, rectal temperature increased from 38.8°C to 39.2°C (P<0.02).
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2.
Cooling the spinal cord to 32.6°C caused plasma free fatty acid (FFA) concentration to increase from a control value of 16.2 mg/100 ml to 22.7 mg/100 ml (P<0.01). This increase in plasma FFA was completely abolished by prior administration of a sympathetic blocking drug.
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These results show that the spinal cord of sheep is cold sensitive and that there is an increase in plasma FFA during spinal cooling, which is mediated via the sympathetic nervous system.
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Bost, J., Dorleac, E.: Action du froid sur le taux plasmatique des acides gras non estérifiés (FFA) chez le Mouton. C.R. Soc. Biol. (Paris)159, 2209–2212 (1965)
Boura, A. L. A., Copp, F. C., Green, A. F., Hodson, H. F., Ruffell, G. K., Sim, M. F., Walton, E., Grivsky, E. M.: Adrenergic neurone-blocking agents related to choline 2,6 Xylyl ether bromide (TM 10), bretylium and guanethidine. Nature (Lond.)191, 1312–1313 (1961)
Brouwer, E.: Report of sub-committee on constants and factors. In Energy metabolism: Proceedings of 3rd symposium. Troon, pp. 441–443. Publ. Eur. Ass. Anim. Prod., No. 11, ed. K. L. Blaxter. London: Academic Press 1965
Calvert, D. T., Clough, D. P., Findlay, J. D., Thompson, G. E.: Hypothalamic cooling, heart production and plasma lipids in the ox. Life Sci.11, 223–229 (1972)
Duncan, W. R. H., Garton, G. A.: The fatty acid composition and intramolecular structure of triglycerides derived from different sites in the body of the sheep. J. Sci. Fd. Agric.18, 99–102 (1967)
Findlay, J. D., Ingram, D. L.: Brain temperature as a factor in the control of thermal polypnoea in the ox (Bos taurus). J. Physiol. (Lond.)155, 72–85 (1961)
Graham, N. McC., Wainman, F. W., Blaxter, K. L., Armstrong, D. G.: Environmental temperature, energy metabolism and heat regulation in sheep. J. agric. Sci. (Cambr.)52, 13–24 (1959)
Hollenberg, C. H., Angel, A.: Relation of fatty acid structure to release and estrification of free fatty acids. Amer. J. Physiol.205, 909–912 (1963)
Jessen, C., Mayer, E. T.: Spinal cord and hypothalamus as core sensors of temperature in the conscious dog. I. Equivalence of responses. Pflügers Arch.324, 189–204 (1971)
Jessen, C., McLean, J. A., Calvert, D. T., Findlay, J. D.: Balanced and unbalanced temperature signals generated in spinal cord of the ox. Amer. J. Physiol.222, 1343–1347 (1972)
Jessen, C., Meurer, K. A., Simon, E.: Steigerung der Hautdurchblutung durch isolierte Wärmung des Rückenmarks am wachen Hund. Pflügers Arch. ges. Physiol.297, 35–52 (1967)
McLean, J. A., Hales, J. R. S., Jessen, C., Calvert, D. T.: Influences of spinal cord temperature on heat exchange of the ox. Proc. Aust. Physiol. Pharmacol. Soc.1, 32 (1970)
Noble, R. C., Thompson, G. E., Moore, J. H.: The effects of the intravenous administration of noradrenaline on the composition of the plasma lipids of sheep. Res. vet. Sci.10, 555–558 (1969)
Simon, E., Rautenberg, W., Thauer, R., Iriki, M.: Die Auslösung von Kältezittern durch lokale Kühlung im Wirbelkanal. Pflügers Arch. ges. Physiol.281, 309–331 (1964)
Thompson, G. E., Clough, D. P.: The effect of intravenous infusion of dopamine on the unesterified fatty acids of sheep plasma. Res. vet. Sci.11, 428–430 (1970)
Thompson, G. E., Clough, D. P.: The effect of cold exposure on plasma lipids of the new-born and adult ox. Quart. J. exp. Physiol.57, 192–198 (1972)
Walther, O. E., Iriki, M., Simon, E.: Antagonistic changes of blood flow and sympathetic activity in different vascular beds following central thermal stimulation. II. Cutaneous and visceral sympathetic activity during spinal cord heating and cooling in anaesthetised rabbits and cats. Pflügers Arch.319, 162–184 (1970)
Webster, A. J. F., Heitman, J. H., Hays, F. L., Olynyk, G. P.: Catecholamines and cold thermogenesis in sheep. Canad. J. Physiol. Pharmacol.47, 719–724 (1969)
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Clough, D.P., Darling, K.F., Findlay, J.D. et al. Cold sensitivity in the spinal cord of sheep. Pflugers Arch. 342, 137–144 (1973). https://doi.org/10.1007/BF00587844
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DOI: https://doi.org/10.1007/BF00587844