The location and properties of preganglionic vagal cardiomotor neurones in the rabbit

D. Jordan, M. E.M. Khalid, N. Schneiderman, K. M. Spyer

Research output: Contribution to journalArticle

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Abstract

The origins of preganglionic vagal neurones which slow the heart in the rabbit have been examined with standard neurophysiological stimulation and recording techniques. The activity of 216 neurones projecting to the right cervical vagus nerve have been recorded in localized areas of the brain stem. Thirty-six of these neurones were classified as cardiomotor neurones since they had properties similar to those described for such neurones in the cat. All had efferent axons in the range of B fibers. They could be synaptically activated by electrical stimulation of the ipsilateral aortic nerve which in the rabbit is solely barosensory. The majority of these neurones (70%) were spontaneously active and those which were normally silent could be made to fire by iontophoretic application of dl-homocysteic acid (an excitant amino acid). This spontaneous, or evoked, activity showed evidence of a pulse rhythm (of baroreceptor origin) and respiratory modulation (firing predominantly during expiration). In response to application of dl-homocysteic acid, the neuronal excitation was usually accompanied by a small but significant bradycardia. Histological examination showed that these neurones were located in both the dorsal vagal nucleus and the nucleus ambiguus.

Original languageEnglish (US)
Pages (from-to)244-250
Number of pages7
JournalPflügers Archiv European Journal of Physiology
Volume395
Issue number3
DOIs
StatePublished - Nov 1 1982
Externally publishedYes

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Keywords

  • Dorsal vagal nucleus
  • Heart rate
  • Nucleus ambiguus
  • Vagal preganglionic neurones

ASJC Scopus subject areas

  • Physiology

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