Tags

Type your tag names separated by a space and hit enter

High levels of circulating angiotensin II shift the open-loop baroreflex control of splanchnic sympathetic nerve activity, heart rate and arterial pressure in anesthetized rats.
J Physiol Sci. 2009 Nov; 59(6):447-55.JP

Abstract

Although an acute arterial pressure (AP) elevation induced by intravenous angiotensin II (ANG II) does not inhibit sympathetic nerve activity (SNA) compared to an equivalent AP elevation induced by phenylephrine, there are conflicting reports as to how circulating ANG II affects the baroreflex control of SNA. Because most studies have estimated the baroreflex function under closed-loop conditions, differences in the rate of input pressure change and the magnitude of pulsatility may have biased the estimation results. We examined the effects of intravenous ANG II (10 microg kg(-1) h(-1)) on the open-loop system characteristics of the carotid sinus baroreflex in anesthetized and vagotomized rats. Carotid sinus pressure (CSP) was raised from 60 to 180 mmHg in increments of 20 mmHg every minute, and steady-state responses in systemic AP, splanchnic SNA and heart rate (HR) were analyzed using a four-parameter logistic function. ANG II significantly increased the minimum values of AP (67.6 +/- 4.6 vs. 101.4 +/- 10.9 mmHg, P < 0.01), SNA (33.3 +/- 5.4 vs. 56.5 +/- 11.5%, P < 0.05) and HR (391.1 +/- 13.7 vs. 417.4 +/- 11.5 beats/min, P < 0.01). ANG II, however, did not attenuate the response range for AP (56.2 +/- 7.2 vs. 49.7 +/- 6.2 mmHg), SNA (69.6 +/- 5.7 vs. 78.9 +/- 9.1%) or HR (41.7 +/- 5.1 vs. 51.2 +/- 3.8 beats/min). The maximum gain was not affected for AP (1.57 +/- 0.28 vs. 1.20 +/- 0.25), SNA (1.94 +/- 0.34 vs. 2.04 +/- 0.42%/mmHg) or HR (1.11 +/- 0.12 vs. 1.28 +/- 0.19 beats min(-1) mmHg(-1)). It is concluded that high levels of circulating ANG II did not attenuate the response range of open-loop carotid sinus baroreflex control for AP, SNA or HR in anesthetized and vagotomized rats.

Authors+Show Affiliations

Department of Cardiovascular Dynamics, Advanced Medical Engineering Center, National Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan. torukawa@res.ncvc.go.jpNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19688237

Citation

Kawada, Toru, et al. "High Levels of Circulating Angiotensin II Shift the Open-loop Baroreflex Control of Splanchnic Sympathetic Nerve Activity, Heart Rate and Arterial Pressure in Anesthetized Rats." The Journal of Physiological Sciences : JPS, vol. 59, no. 6, 2009, pp. 447-55.
Kawada T, Kamiya A, Li M, et al. High levels of circulating angiotensin II shift the open-loop baroreflex control of splanchnic sympathetic nerve activity, heart rate and arterial pressure in anesthetized rats. J Physiol Sci. 2009;59(6):447-55.
Kawada, T., Kamiya, A., Li, M., Shimizu, S., Uemura, K., Yamamoto, H., & Sugimachi, M. (2009). High levels of circulating angiotensin II shift the open-loop baroreflex control of splanchnic sympathetic nerve activity, heart rate and arterial pressure in anesthetized rats. The Journal of Physiological Sciences : JPS, 59(6), 447-55. https://doi.org/10.1007/s12576-009-0055-5
Kawada T, et al. High Levels of Circulating Angiotensin II Shift the Open-loop Baroreflex Control of Splanchnic Sympathetic Nerve Activity, Heart Rate and Arterial Pressure in Anesthetized Rats. J Physiol Sci. 2009;59(6):447-55. PubMed PMID: 19688237.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - High levels of circulating angiotensin II shift the open-loop baroreflex control of splanchnic sympathetic nerve activity, heart rate and arterial pressure in anesthetized rats. AU - Kawada,Toru, AU - Kamiya,Atsunori, AU - Li,Meihua, AU - Shimizu,Shuji, AU - Uemura,Kazunori, AU - Yamamoto,Hiromi, AU - Sugimachi,Masaru, Y1 - 2009/08/18/ PY - 2009/05/21/received PY - 2009/07/19/accepted PY - 2009/8/19/entrez PY - 2009/8/19/pubmed PY - 2010/4/17/medline SP - 447 EP - 55 JF - The journal of physiological sciences : JPS JO - J Physiol Sci VL - 59 IS - 6 N2 - Although an acute arterial pressure (AP) elevation induced by intravenous angiotensin II (ANG II) does not inhibit sympathetic nerve activity (SNA) compared to an equivalent AP elevation induced by phenylephrine, there are conflicting reports as to how circulating ANG II affects the baroreflex control of SNA. Because most studies have estimated the baroreflex function under closed-loop conditions, differences in the rate of input pressure change and the magnitude of pulsatility may have biased the estimation results. We examined the effects of intravenous ANG II (10 microg kg(-1) h(-1)) on the open-loop system characteristics of the carotid sinus baroreflex in anesthetized and vagotomized rats. Carotid sinus pressure (CSP) was raised from 60 to 180 mmHg in increments of 20 mmHg every minute, and steady-state responses in systemic AP, splanchnic SNA and heart rate (HR) were analyzed using a four-parameter logistic function. ANG II significantly increased the minimum values of AP (67.6 +/- 4.6 vs. 101.4 +/- 10.9 mmHg, P < 0.01), SNA (33.3 +/- 5.4 vs. 56.5 +/- 11.5%, P < 0.05) and HR (391.1 +/- 13.7 vs. 417.4 +/- 11.5 beats/min, P < 0.01). ANG II, however, did not attenuate the response range for AP (56.2 +/- 7.2 vs. 49.7 +/- 6.2 mmHg), SNA (69.6 +/- 5.7 vs. 78.9 +/- 9.1%) or HR (41.7 +/- 5.1 vs. 51.2 +/- 3.8 beats/min). The maximum gain was not affected for AP (1.57 +/- 0.28 vs. 1.20 +/- 0.25), SNA (1.94 +/- 0.34 vs. 2.04 +/- 0.42%/mmHg) or HR (1.11 +/- 0.12 vs. 1.28 +/- 0.19 beats min(-1) mmHg(-1)). It is concluded that high levels of circulating ANG II did not attenuate the response range of open-loop carotid sinus baroreflex control for AP, SNA or HR in anesthetized and vagotomized rats. SN - 1880-6562 UR - https://www.unboundmedicine.com/medline/citation/19688237/High_levels_of_circulating_angiotensin_II_shift_the_open_loop_baroreflex_control_of_splanchnic_sympathetic_nerve_activity_heart_rate_and_arterial_pressure_in_anesthetized_rats_ L2 - https://doi.org/10.1007/s12576-009-0055-5 DB - PRIME DP - Unbound Medicine ER -