Angiotensin II acts at AT1 receptors in the nucleus of the solitary tract to attenuate the baroreceptor reflex

Kiyoshi Matsumura, David B. Averill, Carlos M. Ferrario

Research output: Contribution to journalArticle

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Abstract

The object of the current study was to determine if ANG II acts at type 1 (AT1) or type 2 (AT2) receptors in the nucleus of the solitary tract (NTS) to reduce baroreceptor reflex control of renal sympathetic nerve activity (RSNA) and heart rate (HR). Experiments were carried out in urethan- anesthetized Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). Reflex changes in RSNA and HR were elicited by intravenous infusion of either phenylephrine or sodium nitroprusside before and after bilateral microinjection of CV-11974 (AT1 receptor antagonist, 10 pmol), PD-123319 (AT2 receptor antagonist, 100 pmol), or artificial cerebrospinal fluid (aCSF, 50 nl) in the NTS. Mean arterial pressure (MAP)-RSNA and MAP-HR data were fit to logistic functions to analyze the baroreceptor reflex. Baroreceptor reflex sensitivities for RSNA and HR were attenuated in SHR compared with those in WKY rats. Bilateral injection of CV-11974, PD-123319, or aCSF in the NTS of either strain had no effect on baseline arterial pressure, HR, or RSNA. However, CV-11974 injected in the NTS increased significantly (P < 0.01) the sensitivities for baroreceptor reflex control of RSNA and HR in SHR and WKY rats. Neither PD-123319 nor aCSF altered baroreceptor reflex control of RSNA and HR in either SHR or WKY rats. These results demonstrate that endogenous ANG II acts at AT1 receptors of the NTS to attenuate the baroreceptor reflex in SHR as well as in WKY rats.

Original languageEnglish
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume275
Issue number5 44-5
Publication statusPublished - Nov 1 1998

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Solitary Nucleus
Baroreflex
Angiotensin II
Heart Rate
Inbred SHR Rats
Inbred WKY Rats
Kidney
Arterial Pressure
Urethane
Microinjections
Nitroprusside
Phenylephrine
Intravenous Infusions
Reflex
Cerebrospinal Fluid
Injections
candesartan
PD 123319

All Science Journal Classification (ASJC) codes

  • Physiology
  • Physiology (medical)

Cite this

Angiotensin II acts at AT1 receptors in the nucleus of the solitary tract to attenuate the baroreceptor reflex. / Matsumura, Kiyoshi; Averill, David B.; Ferrario, Carlos M.

In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology, Vol. 275, No. 5 44-5, 01.11.1998.

Research output: Contribution to journalArticle

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