Summary
In chloralose-urethane anaesthetized cats, low-threshold baroreceptor afferents of the carotid sinus and aortic nerves were stimulated electrically. Evoked responses were recorded within the nucleus tractus solitarii near the obex. At a certain electrode position in this area an evoked potential (E. P.) was elicited by stimulation of the homolateral carotid sinus or aortic nerve as well as the contralateral sinus or aortic nerve.
At this site an interaction of these four baroreceptor nerves was demonstrated by testing the E. P. of one nerve after a conditioning stimulation of another nerve. Simultaneous E. P.'s did not show arithmetical summation. A strong reduction of the test-E.P. (mean value of reduction: 50%) occurred with a conditioning-testing interval of 10–20 msec. The test-E. P. came back to the control amplitude at an interval of 100–150 msec.
Neither picrotoxin nor strychnine changed the time course or extent of these interactions.
It was further observed that the most effective conditioning-testing interval for inhibition of test response corresponded closely to the difference between the arrival times of arotic and sinus nerve activities evoked by the cardiovascular pulse (aortic 16±5 msec before sinus nerve).
Similar content being viewed by others
References
Cottle, M. K.: Degeneration studies of primary afferents of IXth and Xth cranial nerves in the cat. J. comp. Neurol.122, 329–345 (1964).
Crill, W. E., Reis, D. J.: Distribution of carotid sinus and depressor nerves in cat brain stem. Amer. J. Physiol.214, 269–276 (1968).
Douglas, W. E., Schaumann, W.: A study of the depressor and pressor components of the cat's carotid sinus and aortic nerves using electrical stimuli of different intensities and frequencies. J. Physiol. (Lond.)132, 173–186 (1956).
Eccles, J. E.: The physiology of synapsis. Berlin-Göttingen-Heidelberg: Springer 1964.
Gabriel, M., Seller, H.: Interaction of the baroreceptor inputs at the secondary neurons in regard to their temporal arrival. Pflügers Arch.307, R43 (1969).
Hellner, K. A., v. Baumgarten, R.: Über ein Endigungsgebiet afferenter, kardiovasculärer Fasern des Nervus vagus im Rautenhirn der Katze. Pflügers Arch. ges. Physiol.273, 223–234 (1961).
Humphrey, D. R.: Neuronal activity in the medulla oblongata of cat evoked by stimulation of the carotid sinus nerve. In: Baroreceptors and hypertension. Ed. by P. Kezdi. Oxford: Pergamon Press 1967.
Ingram, W. R., Dawkins, E. A.: The intramedullary course of afferent fibers of the vagus nerve in the cat. J. comp. Neurol.82, 157 (1945).
Jarausch, K. H., Ullrich, V. J.: Zur Technik der Entnahme von Harnproben aus einzelnen Sammelrohren der Säugetierniere mittels Polyäthylen-Capillaren. Pflügers Arch. ges. Physiol.264, 88–94 (1957).
Kerr, F. W. L.: Facial, vagal and glossopharyngeal nerves in the cat. Arch. Neurol. (Chic.)6, 264–281 (1962).
Koch, E.: Die reflektorische Selbststeuerung des Kreislaufs. Dresden: Steinkopff 1931.
Mollica, A. J., Rossi, G. F., Venturelli, E.: Sopra un metodo di localizzatione di microelettrodi metallici nel tessuto nervoso (microelettrolisi). Boll. Soc. ital. Biol. sper.30, 272 (1954).
Rudomin, P.: Presynaptic inhibition induced by vagal afferent volleys. J. Neurophysiol.30, 964–981 (1967).
Sampson, S. R., Biscoes, T. J.: Electrical potentials evoked in the brain stem by stimulation of the sinus nerve. Brain Res.9, 398–402 (1968).
Seller, H., Illert, M.: The localization of the first synapse in the carotid sinus baroreceptor reflex pathway and its alteration of the afferent input. Pflügers Arch.306, 1–19 (1969).
Stegemann, J., Müller-Bütow, H.: Zur regeltheoretischen Analyse des Blutkreislaufes. I–IV. Pflügers Arch. ges. Physiol.287, 247–285 (1966).
Wall, P. D.: Excitability changes in afferent fibre terminations and their relation to slow potentials. J. Physiol. (Lond.)142, 1–21 (1958).
Author information
Authors and Affiliations
Additional information
This work was supported by the Deutsche Forschungsgemeinschaft.
Rights and permissions
About this article
Cite this article
Gabriel, M., Seller, H. Interaction of baroreceptor afferents from carotid sinus and aorta at the nucleus tractus solitarii. Pflugers Arch. 318, 7–20 (1970). https://doi.org/10.1007/BF00588539
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00588539
Key-words
- Carotid Sinus Nerve Stimulation
- Aortic Nerve Stimulation
- Nucleus Tractus Solitarii
- Evoked Potential
- Baroreceptor Reflex Control