Pregnancy alters cardiac receptor afferent discharge in rats

Tina Hines*, Tracy M. Hodgson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Reflex effects of cardiac receptor (CR) stimulation are attenuated in pregnant rats. We tested whether CR afferent discharge is reduced during pregnancy by measuring single fiber activity in response to increases in right atrial pressure (RAP) in anesthetized pregnant and virgin rats with sinoaortic denervation. Single fiber activity was isolated from fine filaments of the right cervical vagus nerve. Changes in CR discharge, RAP, and arterial pressure were recorded in response to atrial saline injections (25-300 μl). Resting RAP was similar between groups, and spontaneous CR discharge was similar in pregnant rats (1.95 ± 0.21 Hz) and in low-frequency (LF) receptors in virgin rats (1.30 ± 0.2 Hz). In virgin, but not pregnant rats, a subset (24%) of CR had higher-frequency (HF) spontaneous discharge (9.91 ± 1.19 Hz). During stimulation, the level of RAP above which CR firing increased was significantly higher in pregnant rats, but CR activity was clustered into an LF discharge range. Thus gestation appears to reduce the activity of CR afferents, possibly by increasing stimulus threshold or by selective inactivation of a subset of HF discharging receptors.

Original languageEnglish (US)
Pages (from-to)R149-R156
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Issue number1 47-1
StatePublished - Jan 2000


  • Pentobarbital sodium
  • Right atrium
  • Single fibers
  • Vagus nerve

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


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