Aortic depressor nerve stimulation does not impede the dynamic characteristics of the carotid sinus baroreflex in normotensive or spontaneously hypertensive rats

Toru Kawada, Michael J. Turner, Shuji Shimizu, Masafumi Fukumitsu, Atsunori Kamiya, Masaru Sugimachi

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Recent clinical trials in patients with drug-resistant hypertension indicate that electrical activation of the carotid sinus baroreflex (baroreflex activation therapy) can reduce arterial pressure (AP) for more than a year. To examine whether the electrical stimulation from one baroreflex system impedes normal short-term AP regulation via another unstimulated baroreflex system, we electrically stimulated the left aortic depressor nerve (ADN) while estimating the dynamic characteristics of the carotid sinus baroreflex in anesthetized normotensive Wistar-Kyoto (WKY, n=8) rats and spontaneously hypertensive rats (SHR, n=7). Isolated carotid sinus regions were perturbed for 20 min using a Gaussian white noise signal with a mean of 120 mmHg for WKY and 160 mmHg for SHR. Tonic ADN stimulation (2 Hz, 10 V, 0.1-ms pulse width) decreased mean sympathetic nerve activity (73.4±14.0 vs. 51.6±11.3 arbitrary units in WKY, P = 0.012; and 248.7±33.9 vs. 181.1±16.6 arbitrary units in SHR, P = 0.018) and mean AP (90.8±6.6 vs. 81.2±5.4 mmHg in WKY, P=0.004; and 128.6±9.8 vs. 114.7±10.3 mmHg in SHR, P = 0.009). The slope of dynamic gain in the neural arc transfer function from carotid sinus pressure to sympathetic nerve activity was not different between trials with and without the ADN stimulation (12.55±0.93 vs. 13.03±1.28 dB/decade in WKY, P = 0.542; and 17.37±1.01 vs. 17.47±1.64 dB/decade in SHR, P = 0.946). These results indicate that the tonic ADN stimulation does not significantly modify the dynamic characteristics of the carotid sinus baroreflex.

Original languageEnglish
Pages (from-to)R787-R796
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume312
Issue number5
DOIs
Publication statusPublished - May 30 2017

Keywords

  • Arterial pressure
  • Gaussian white noise
  • Sympathetic nerve activity
  • Transfer function

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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