The Effects of Changes in Arterial Pressure on Sinus Nerve Efferent Activity
The carotid body is a peripheral arterial chemoreceptor which senses arterial blood pH, PC0 2 and P0 2. Neuronal activity from the carotid body is conveyed to the central nervous system by the carotid sinus nerve, a branch of the ninth cranial nerve. In 1968 Biscoe and Sampson1 recorded neuronal activity from the central end of the sinus nerve. This activity was of two types. The first type displayed a respiratory rhythm in firing rate and was shown to arise from the sympathetic nervous system via the superior cervical ganglion. The second type appeared to originate directly from the central nervous system and displayed a random firing pattern. This second type of activity is termed sinus nerve efferent activity, and has been shown by Sampson and Biscoe2 and by Neil and O’Regan3, 4 to be capable of inhibiting carotid chemoreceptor afferent activity. We have investigated the response of sinus nerve efferent activity to changes in systemic arterial pressure induced passively by bleeding and by reinfusion of the animal’s own blood. Some of these results have been presented to the Physiological Society5.
KeywordsArterial Pressure Carotid Body Superior Cervical Ganglion Systemic Arterial Pressure Ninth Cranial Nerve
Unable to display preview. Download preview PDF.
- 1.Biscoe, T.J. and Sampson, S.R.: Rhythmical and non-rhythmical spontaneous activity recorded from the central cut end of the sinus nerve. J. Physiol. 196:327–328, 1968.Google Scholar
- 2.Sampson, S.R. and Biscoe, T.J.: Efferent control of the carotid body chemoreceptor. Experientia. Basel. 26: 261–262, 1970.Google Scholar
- 5.Majcherczyk, S., Ponte, J. and Willshaw, P.: Modification of sinus nerve efferent activity by changes in arterial pressure. Communication to Physiological Society, June, 1977. J.Physiol. (in press).Google Scholar
- 6.Goodman, N.W.: Efferent inhibition of arterial chemoreceptors and stimulation of the sinus nerve. In: The Peripheral Arterial Chemoreceptors, edited by M.J. Purves. Cambridge University Press, 1975, pp. 241–252.Google Scholar
- 7.Majcherczyk, S. and Willshaw, P.: Inhibition of peripheral chemoreceptor activity during superfusion with an alkaline csf of the ventral brainstem surface of the cat. J. Physiol. 23l:26–27P, 1973.Google Scholar
- 9.Purves, M.J.: The Physiology of the Cerebral Circulation. Cambridge University Press, 1972, p. 170.Google Scholar
- 10.Betz, E.: Cerebral blood flow: its measurement and regulation. Phys. Rev. 52(3):595–630, 1972.Google Scholar
- 11.Floyd, W.F. and Neil, E.: The influence of the sympathetic innervation of the carotid bifurcation on chemoreceptor and baroreceptor activity in the cat. Arch. Intern. Pharmacodyn. 91:230–239, 1952.Google Scholar