Summary
The baroreceptor reflex is thought to counteract both a rise and a fall in arterial blood pressure, but the evidence for this is incomplete. In 19 anesthetized rabbits, the relationship between blood pressure/aortic nerve activity and efferent sympathetic activity in renal and splanchnic nerves was therefore investigated during induced rise and fall of arterial pressure. Baroreceptor activity increased and sympathetic activity decreased with raised pressure. In contrast, reduction of baroreceptor activity during acute hemorrhagic hypotension had little or no effect on activity in the two sympathetic nerves. Following complete barodenervation, however, sympathetic activity rose on average to 238% of control values. We therefore conclude that the baroreceptor reflex mainly counteracts a rise in arterial blood pressure. Reduction of baroreceptor activity in the first few minutes of acute hemorrhagic hypotension does not lead to increased sympathetic activity. The small activity remaining in baroreceptor nerves at low pressures had a very potent sympathetic inhibitory effect.
Similar content being viewed by others
References
Aars, H., Akre, S.: Effect of angiotensin on sympathetic nerve activity. Acta physiol. scand.74, 134–141 (1968).
—, Leraand, S.: A method for quantitative analysis of aortic nerve activity. J. appl. Physiol.24, 416–418 (1968).
Akre, S., Aars, H.: Sympathetic responses to changes in systemic blood pressure. Acta physiol. scand.77, Suppl. 330, 92 (1969).
Allison, J. L., Sagawa, K., Kumada, M.: An open-loop analysis of the aortic arch barostatic reflex. Amer. J. Physiol.217, 1576–1584 (1969).
Åström, A., Crafoord, J.: Afferent and efferent activity in the renal nerves of cats. Acta physiol. scand.74, 69–78 (1968).
Edis, A. J., Shepherd, J. T.: Autonomic control of the peripheral vascular system. Arch. intern. Med.125, 716–724 (1970).
Engelhorn, R.: Aktionspotentiale der Nierennerven. Naunyn-Schmiedebergs Arch. exp. Path. Pharmak.231, 219–234 (1957).
Folkow, B., Johansson, B., Löfving, B.: Aspects of functional differentiation of the sympatho-adrenergic control of the cardiovascular system. Med. exp. (Basel)4, 321–328 (1961).
Gernandt, B. E.: A study of the respiratory reflexes elicited from the aortic and carotid bodies. Acta physiol. scand.11, Suppl. 35, 1–81 (1946).
—, Liljestrand, G., Zotterman, Y.: Efferent impulses in the splanchnic nerve. Acta physiol. scand.11, 230–247 (1946).
Gootman, P. M., Cohen, M. I.: Efferent splanchnic activity and systemic arterial pressure. Amer. J. Physiol.219, 897–903 (1970).
Hainsworth, R., Ledsome, J. R., Carswell, F.: Reflex responses from aortic baroreceptors. Amer. J. Physiol.218, 423–429 (1970).
Heymans, C., Neil, E.: Reflexogenic areas of the cardiovascular system. London: J. & A. Churchill Ltd. 1958.
Kalkoff, W., Plischke, K. H., Rath, F. W.: Chemoreception und lokale Adrenalinwirkung am Sinus caroticus. Pflügers Arch. ges. Physiol.289, 122–140 (1966).
Kenney, R. A., Neil, E.: The contribution of aortic chemoreceptor mechanisms to the maintenance of arterial blood pressure of cats and dogs after haemorrhage. J. Physiol. (Lond.)112, 223–228 (1951).
Kezdi, P., Geller, E.: Baroreceptor control of postganglionic sympathetic nerve discharge. Amer. J. Physiol.214, 427–435 (1968).
Landgren, S., Neil, E.: The contribution of carotid chemoreceptor mechanisms to the rise of blood pressure caused by carotid occlusion. Acta physiol. scand.23, 152–157 (1951).
——: Chemoreceptor impulse activity following haemorrhage. Acta physiol. scand.23, 158–167 (1951).
Lundgren, O., Lundwall, J., Mellander, S.: Range of sympathetic discharge and reflex adjustments in skeletal muscle during hemorrhagic hypotension. Acta physiol. scand.62, 380–390 (1964).
Ninomiya, I., Irisawa, H.: Summation of baroceptor reflex effects on sympathetic nerve activities. Amer. J. Physiol.216, 1330–1336 (1969).
Öberg, B., Thorén, P.: Increased activity in vagal cardiac afferents correlated to the appearance of reflex bradycardia during severe hemorrhage in cats. Acta physiol. scand.80, 22–23 A (1970).
Peterson, L. H.: Regulation of blood vessels. Circulation21, 749–759 (1960).
Pinardi, G.: Effects of denervation on the hemodynamics of the spleen during irreversible shock. Acta physiol. lat.-amer.18, 248–252 (1968).
Scher, A. M.: Control of arterial blood pressure: Measurement of pressure and flow. In: T. C. Ruch and H. D. Patton: Physiology and biophysics, p. 662. Philadelphia-London: W. B. Saunders 1965.
Thämer, V., Weidinger, W., Kirchner, F.: Sympathische Aktionspotentiale in hämorrhagischen Schock. Z. Kreisl.-Forsch.58, 472–484 (1969).
Weidinger, H., Fedina, L., Kehrel, H.: Der Einfluß von Adrenalin auf die Tätigkeit des “Sympathicus”. Pflügers Arch. ges. Physiol.278, 229–240 (1963).
—, Huber, U.: Beziehung zwischen sympathischen Aktionspotentialen, zentraler Atmung und Blutdruck bei chronisch decrebrierten Katzen. Pflügers Arch. ges. Physiol.281, 259–270 (1964).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Aars, H., Akre, S. Sympathetic nervous response to induced fall and rise of arterial blood pressure in anesthetized rabbits. Pflugers Arch. 326, 223–230 (1971). https://doi.org/10.1007/BF00592503
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00592503