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The effects of blood osmolality changes on cat carotid body chemoreceptors in vivo


The possibility that carotid chemoreceptors respond to changes in plasma osmolality was investigated in the cat, perfusing the carotid artery with blood made hyper- or hypo-osmotic and recording chemoreceptor activity from carotid nerve fibers. Blood made hyperosmotic with sucrose or NaCl reduced the chemoreceptor discharge, while hypoosmotic blood increased chemoreceptor activity. The minimal osmolality variation necessary to obtain a detectable frequency change was 3–8% of the control. Frequency changes of 30% of the control were obtained with a 20% variation in osmolality. The frequency variations produced by the osmotic changes lasted as long as the infusion was maintained (up to 15 min). In some instances a rebound was observed when iso-osmotic saline was perfused again. A transient change in frequency and a clear rebound were obtained when blood made hyperosmotic with glycerol was perfused. These effects probably reflect a rapid change in intracellular osmolality due to the free passage of glycerol across cellular membranes.

The modifications in chemoreceptor activity consecutive to osmolality variations are the opposite of those observed in isolated and superfused carotid bodies. As it is known that osmolality values affect the smooth muscle of the blood vessels, we conclude that our results are mainly produced by changes in carotid body blood flow due to a direct effect of hyper- and hypo-osmotic solutions on vascular muscle tone. Chemoreceptor excitation during a decrease in blood osmolality may contribute reflexly to the increased vascular resistance observed during acute osmolality reductions in man.

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  1. Biscoe, T. J., Bradley, G. W., Purves, M. J.: The relation between carotid body chemoreceptor discharge, carotid sinus pressure and carotid body blood flow. J. Physiol. (Lond.)208, 99–120 (1970)

    Google Scholar 

  2. Eyzaguirre, C., Nishi, K.: Effects of different ions on resting polarization and on the mass receptor potential of carotid body chemoreceptors. J. Neurobiol.7, 417–434 (1976)

    Google Scholar 

  3. Eyzaguirre, C., Baron, M., Gallego, R.: Effects of temperature and stimulating agents on carotid body cells. In: Chemoreception in the carotid body. (H. Acker, S. Fidone, D. Pallot, C. Eyzaguirre, D. W. Lubbers and R. W. Torrance, eds.), pp. 71–78. Berlin-Heidelberg-New York, Springer 1977

    Google Scholar 

  4. Gallego, R., Eyzaguirre, C.: Effects of osmotic pressure changes on the carotid body of the cat in vitro. Fed. Proc.35, 404 (1976)

    Google Scholar 

  5. Gallego, R., Eyzaguirre, C., Monti-Bloch, L.: Thermal and osmotic responses of arterial receptors. J. Neurophysiol. (in press, 1979)

  6. Honig, A., Flemming, B., Rauhut, U., Roloff, D., Boege, R., Matthiess, P., Walther, J.: Die Funktion der innervierten Nieren während der Reizung der Karotis-Chemorezeptoren bei konstantem Perfusionsdruck. Acta Biol. Med. Germ.34, 1025–1036 (1975)

    Google Scholar 

  7. Johansson, B., Jonsson, O.: Cell volume as a factor influencing electrical and mechanical activity of vascular smooth muscle. Acta Physiol. Scand.72, 456–468 (1968)

    Google Scholar 

  8. Marshall, R. J., Shepherd, J. T.: Effect of injections of hypertonic solutions on blood flow through the femoral artery of the dog. Am. J. Physiol.197, 951–954 (1959)

    Google Scholar 

  9. Moses, A. M., Miller, M.: Osmotic influences on the release of vasopressin. In: Handbook of physiology. (W. H. Sawyer and E. Knobil, eds.) Vol. 4, pp. 225–242, Baltimore: Williams and Wilkins Co. 1974

    Google Scholar 

  10. Ottosson, D.: The effect of osmotic pressure changes on the isolated muscle spindle. Acta Physiol. Scand.64, 93–105 (1965)

    Google Scholar 

  11. Overbeck, H. W., Pamnani, M. B.: Vascular responses to plasma hypoosmolality in man. Proc. Soc. Exp. Biol. Med.150, 331–336 (1975)

    Google Scholar 

  12. Share, L., Levy, M. N.: Effect of carotid chemoreceptor stimulation on plasma antidiuretic hormone titer. Am. J. Physiol.210, 157–161 (1966)

    Google Scholar 

  13. Verney, E. B.: The antidiuretic hormone and the factors which determine its release. Proc. R. Soc. Lond. [B]135, 25–105 (1947)

    Google Scholar 

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Gallego, R., Belmonte, C. The effects of blood osmolality changes on cat carotid body chemoreceptors in vivo. Pflugers Arch. 380, 53–58 (1979). https://doi.org/10.1007/BF00582612

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Key words

  • Osmolality
  • Carotid body
  • Chemoreceptors
  • Carotid nerve
  • Osmotic pressure