Visceral afferent activation-induced changes in sympathetic nerve activity and baroreflex sensitivity

Tarek M. Saleh, Barry J. Connell, Gary V. Allen

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

The following experiments were done to determine whether changes in baroreflex sensitivity evoked by cervical vagus nerve stimulation are due to sympathoexcitation mediated by the parabrachial nucleus. The relative contribution of cardiopulmonary and general gastric afferents within the cervical vagus nerve to the depression in baroreflex sensitivity are also investigated. Male Sprague-Dawley rats anesthetized with thiobutabarbital sodium (50 mg/kg) were instrumented to measure blood pressure and heart rate or for the continuous monitoring of renal sympathetic nerve activity. Baroreflex sensitivity was measured using bolus injections of phenylephrine. Electrical stimulation of the cervical vagus (with or without the aortic depressor nerve) or the abdominal vagus nerve produced a significant increase in renal nerve activity and a decrease in baroreflex sensitivity. Both of these effects were blocked after the microinjection of lidocaine into the parabrachial nucleus before nerve stimulation. Therefore, we conclude that an increase in the activity of cardiac, pulmonary, or general gastric afferents mediated the increased sympathetic output and decreased baroreflex sensitivity via a pathway involving the parabrachial nucleus.

Original languageEnglish
Pages (from-to)R1780-R1791
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume276
Issue number6 45-6
DOIs
Publication statusPublished - Jun 1999

ASJC Scopus Subject Areas

  • Physiology
  • Physiology (medical)

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