Summary
Metabolic and cardiovascular parameters were studied in four western chipmunks, genusEutamias, to elucidate the mechanisms underlying the maintenance of normal aerobic metabolism while the heart rate were profoundly depressed (Jones and Wang, 1976). It was postulated that cardiovascular adaptations involving either an increase of stroke volume and/or an increase of arterial-venous oxygen difference (A-V O2) must have evolved to account for such alterations (Jones and Wang, 1976). Simultaneous measurements of O2 consumption, heart rate and A-V O2 were made in anesthetized animals at thermal neutral temperature of 25°C. The mean cardiac output ranged between 16.2–23.5 ml/min, and the calculated stroke volume was between 0.032–0.057 ml/beat, not atypical for similar sized mammals (Table 1). Measurements of heart weight as an indirect indicator for stroke volume also indicated normal stroke volume in the chipmunks (Table 2). The mean A-V O2, on the other hand, was between 5.6–10.4 vol % (Table 1), comparatively greater than the 4–6 vol % typical of resting mammals. The measured hematocrit, hemoglobin concentration, red blood cell counts, and blood volume, were within the range of values for similar sized mammals (Table 3), suggesting normal O2 capacity as well as O2 content carried in blood. Taken together, it was concluded that the major cardiovascular modification in the chipmunks while accomplishing normal aerobic metabolism under profoundly depressed heart rates is by the increased ability to extract O2 across the capillary beds. Possible mechanisms relating to this adaptation are discussed.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Adolph, E.F.: Quantitative relations in the physiological constitutions of mammals. Science109, 579–585 (1949)
Bartels, H.: Some aspects of circulatory and respiratory functions in mammals. Amer. Heart J.72, 1–6 (1966)
Crosby, W.H., Munn, J.I., Furth, F.W.: Standardizing a method for clinical hemoglobinometry. U.S. armed Forces med. J.5, 693–703 (1954)
Dhindsa, D.S., Metcalfe, J., Hoversland, A.S.: Comparative studies of the respiratory functions of mammalian blood. IX. Ring-tailed lemur (Lemur catta) and black lemur (Lemur macaca). Resp. Physiol.15, 331–342 (1972)
Drabkin, D.L.: Spectrophotometric studies: VII. The establishment of precise spectrophotometric constants for cytochrome C and hemin derivatives upon an iron basis. J. biol. Chem.140, 373–385 (1941)
Drabkin, D.L.: Distribution and metabolic aspects of derivatives of iron protoporphrin (Hemin). Fed. Proc.7, 483–492 (1948)
Frisancho, A.R.: Functional adaptation to high altitude hypoxia. Science187, 313–319 (1975)
Gregerson, M.I.: An analysis of colorimetric methods in relation to plasma volume determinations. J. Lab. clin. Med.23, 423 (1938)
Gregerson, M.L., Gibson, J.G. II, Stead, E.A.: Plasma volume determinations with dyes: errors in colorimetry: use of blue dye T-1824. Amer. J. Physiol.113, 54 (1935)
Hall, E.R., Kelson, H.R.: The mammals of North America, p. 546. New York: The Ronald Press Co. 1959
Hall, F.G.: Hemoglobin and oxygen: affinities in seven species ofSciuridae. Science148, 1350–1351 (1965)
Iberall, A.S.: Blood flow and oxygen uptake in mammals. Ann. Biomed. Engn.1, 1–8 (1972)
Jones, D.L.: Metabolic and cardiovascular adaptations in the Western chipmunks, genusEutamias, p. 95. M.Sc. Thesis. University of Alberta, Edmonton, Alberta (1974)
Jones, D.L., Wang, L.C.-H.: Metabolic and cardiovascular adaptations in the Western Chipmunks, genusEutamias. J. comp. Physiol.105, 219–231 (1976)
Kirk, B.W., Raber, M.B.: A practical apparatus for rapid determination of blood oxygen content. J. appl. Physiol.34, 724–725 (1973)
Morrison, P., Rosenmann, M., Sealander, J.A.: Seasonal variation of myoglobin in the northern red-backed vole. Amer. J. Physiol.211, 1305–1308 (1966)
Nadler, C.F.: Contributions of chromosomal analysis to the systematics of North American chipmunks. Amer. Midland Nat.72, 298–312 (1964)
Parer, J.T., Metcalfe, J.: Oxygen transport by blood in relation to body size. Nature (Lond.)215, 653–654 (1967)
Popovic, V., Berger, R.: Semichronic implantation of large cannulas in the aorta and right ventricles of white rats. Angiologica5, 8–13 (1968)
Popovic, V., Kent, D.M., Popovic, P.: Technique of permanent cannulation of right ventricle in rats and ground squirrels. Proc. Soc. exp. Biol. (N.Y.)113, 599–602 (1963)
Popovic, V., Popovic, P.: Permanent cannulation of aorta and vena cava in rats and ground squirrels. J. appl. Physiol.15, 727–728 (1960)
Rand, P.W., Norton, J.W., Barker, N., Lovell, M.: Influence of athletic training on hemoglobinoxygen affinity. Amer. J. Physiol.224, 1334–1337 (1973)
Rosenmann, M., Morrison, P.R.: Seasonal augmentation of myoglobin in the snowshoe hare. J. biol. Chem.240, 3353–3356 (1965)
Sealander, J.A.: Seasonal changes in blood values of deer mice and other small mammals. Ecology43, 107–119 (1962)
Sokal, R.R., Rohlf, F.J.: Biometry, pp. 776. San Francisco, California: W.H. Freeman and Co. 1969
Spector, W.S. (ed.): Handbook of biological data. Philadelphia: W.B. Saunders Co. 1956
Stahl, W.R.: Scaling of respiratory variables in mammals. J. appl. Physiol.22, 453–460 (1967)
Steel, R.G.D., Torrie, T.H.: Principles and procedures of statistics, p. 481 New York: McGraw-Hill 1960
Tucker, V.A.: Method for oxygen content and dissociation curves on microliter blood samples. J. appl. Physiol.23, 410–414 (1967)
Weinberg, G.H., Schumaker, J.A.: Statistics on intuitive approach, p. 362 Belmont: Brooks/Cole Pub. Co. 1969
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Jones, D.L., Wang, L.C.H. Adaptive cardiovascular modifications in the western chipmunks genusEutamias . J Comp Physiol B 112, 307–315 (1976). https://doi.org/10.1007/BF00692301
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00692301