Neurones in a discrete region of the nucleus tractus solitarius are required for the Breuer‐Hering reflex in rat.

A. C. Bonham*, D. R. McCrimmon

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

137 Scopus citations

Abstract

1. The Breuer‐Hering reflex consists of a shortening of inspiration and lengthening of expiration in response to afferent input from slowly adapting pulmonary stretch receptors (SAR). We hypothesized that neurones in a discrete region of the nucleus tractus solitarius (NTS) are required for producing the reflex. Accordingly, the present studies were undertaken to: (1) identify sites in the NTS in which chemical excitation of neurones inhibited phrenic nerve discharge in a manner consistent with SAR activation, (2) determine whether localized interruption of synaptic transmission prevented the Breuer‐Hering reflex, and (3) determine whether these regions contained pump cells and SAR terminal afferents. Studies were carried out in urethane‐anaesthetized rats. 2. Injection of picomoles of an excitatory amino acid, DL‐homocysteic acid (DLH), in the NTS, at the rostrocaudal level of the area postrema and immediately medial to the tractus solitarius, silenced phrenic nerve activity similarly to that expected from SAR activation. These apnoeas lasted from 3 to 43 s and were produced with little or no change in arterial pressure or heart rate. 3. The Breuer‐Hering reflex, physiologically activated by maintaining lung inflation, was transiently impaired by interruption of synaptic transmission following injections of cobalt chloride in the DLH‐responsive region. 4. Pump cell (SAR interneurone) and SAR afferent activity were recorded at the site in which DLH produced apnoea. 5. Taken together, the results of chemical excitation, interruption of synaptic transmission and extracellular recording, suggest that cells within a discrete region of the NTS, probably pump cells, are necessary for the production of the Breuer‐Hering reflex.

Original languageEnglish (US)
Pages (from-to)261-280
Number of pages20
JournalThe Journal of Physiology
Volume427
Issue number1
DOIs
StatePublished - Aug 1 1990

ASJC Scopus subject areas

  • Physiology

Fingerprint Dive into the research topics of 'Neurones in a discrete region of the nucleus tractus solitarius are required for the Breuer‐Hering reflex in rat.'. Together they form a unique fingerprint.

Cite this