HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Johnson, C D Articles by Gilbey, M P Search for Related Content PubMed PubMed Citation Articles by Johnson, C D Articles by Gilbey, M P

Department of Physiology, Royal Free Hospital School of Medicine, London, UK.

1. In anaesthetized rats, using a focal recording technique, activity was recorded from single sympathetic postganglionic neurones innervating the caudal ventral artery of the tail. The following hypotheses were tested: (i) that the frequency of the dominant rhythmic discharge of the neurones can be different from the frequency of the central respiratory rhythm (as indicated by rhythmic phrenic discharge); and (ii) that the dominant sympathetic rhythm is not reliant on afferent feedback carried in aortic, sinus and vagus nerves. 2. Four types of preparation were used: spontaneously breathing (group 1), artificially ventilated (group 2), artificially ventilated with vagi cut (group 3), and artificially ventilated with vagus and sino-aortic denervation (group 4). 3. The frequencies of the dominant sympathetic rhythm under control conditions were: group 1, 0.91 +/- 0.12 Hz (mean +/- S.E.M., n = 5); group 2, 0.81 +/- 0.04 Hz (n = 18); group 3, 0.83 +/- 0.03 Hz (n = 17); group 4, 0.95 +/- 0.06 Hz (n = 11). The frequency of the dominant sympathetic rhythm was different from that of the phrenic rhythm in thirty-five out of fifty-one cases. 4. The mean frequency of the dominant sympathetic rhythm was not influenced significantly by hypocapnic apnoea. 5. Hyperthermia increased the frequency of the phrenic rhythm whilst decreasing that of the dominant sympathetic rhythm. 6. In all cases the frequency of the dominant sympathetic rhythm was different from that of the artificial ventilation cycle. 7. It is concluded that the frequency of the dominant sympathetic rhythm can be different from that of central respiratory drive and that it is not "driven' by afferent feedback relayed via sinus, aortic and vagus nerves. 8. It is proposed that the dominant sympathetic rhythm is unlikely to be generated by a central respiratory oscillator.

This article has been cited by other articles:

				C. Lamont, C. Vial, R. J. Evans, and W. G. Wier P2X1 receptors mediate sympathetic postjunctional Ca2+ transients in mesenteric small arteries Am J Physiol Heart Circ Physiol, December 1, 2006; 291(6): H3106 - H3113. [Abstract] [Full Text] [PDF]

				A. D. Whyment, J. M. M. Wilson, L. P. Renaud, and D. Spanswick Activation and integration of bilateral GABA-mediated synaptic inputs in neonatal rat sympathetic preganglionic neurones in vitro J. Physiol., February 15, 2004; 555(1): 189 - 203. [Abstract] [Full Text] [PDF]

				E. Bradley, A. Law, D. Bell, and C. D. Johnson Effects of varying impulse number on cotransmitter contributions to sympathetic vasoconstriction in rat tail artery Am J Physiol Heart Circ Physiol, June 1, 2003; 284(6): H2007 - H2014. [Abstract] [Full Text] [PDF]

				J. L. Morris, P. Jobling, and I. L. Gibbins Botulinum neurotoxin A attenuates release of norepinephrine but not NPY from vasoconstrictor neurons Am J Physiol Heart Circ Physiol, December 1, 2002; 283(6): H2627 - H2635. [Abstract] [Full Text] [PDF]