Acute effects of intravenous nifedipine or azelnidipine on open-loop baroreflex static characteristics in rats

Hiromi Yamamoto, Toru Kawada, Shuji Shimizu, Atsunori Kamiya, Michael J. Turner, Shunichi Miyazaki, Masaru Sugimachi

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Aims To assess the acute effects of intravenous azelnidipine, a third-generation L-type calcium channel blocker, on sympathetic outflow from the central nervous system and to compare the effects of intravenous azelnidipine with those of intravenous nifedipine. Main methods In anesthetized Wistar Kyoto rats, carotid sinus baroreceptor regions were isolated. Changes in sympathetic nerve activity (SNA) and arterial pressure (AP) in response to a stepwise baroreceptor pressure input were examined before and during intravenous nifedipine or azelnidipine (for each: 100 μg/kg bolus followed by 300 μg/kg/h infusion, n = 6). Key findings Nifedipine significantly reduced the range of the AP response from 76.8 ± 7.4 to 45.4 ± 7.0 mm Hg (P < 0.01) but did not affect the range of the SNA response (from 84.4 ± 5.1 to 85.9 ± 10.2%) or the SNA maximum gain (from 2.26 ± 0.28 to 2.35 ± 0.55%/mm Hg). Similarly, azelnidipine significantly reduced the range of the AP response from 62.4 ± 3.9 to 31.4 ± 4.1 mm Hg (P < 0.01) but did not affect the range of the SNA response (from 71.2 ± 5.5 to 74.9 ± 7.2%) or the SNA maximum gain (from 1.64 ± 0.17 to 2.08 ± 0.26%/mm Hg). Significance A depressor dose of nifedipine or azelnidipine does not have an acute sympathoinhibitory effect in normotensive Wistar Kyoto rats even when the level of SNA was varied over the entire operating range of the carotid sinus baroreflex.

Original languageEnglish
Pages (from-to)37-41
Number of pages5
JournalLife Sciences
Volume126
DOIs
Publication statusPublished - Apr 1 2015
Externally publishedYes

Fingerprint

Baroreflex
Nifedipine
Rats
Carotid Sinus
Arterial Pressure
Pressoreceptors
Inbred WKY Rats
L-Type Calcium Channels
Calcium Channel Blockers
Neurology
Central Nervous System
azelnidipine
Pressure

Keywords

  • Azelnidipine
  • Carotid sinus baroreflex
  • Nifedipine
  • Open-loop system analysis
  • Sympathetic nerve activity

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

Cite this

Acute effects of intravenous nifedipine or azelnidipine on open-loop baroreflex static characteristics in rats. / Yamamoto, Hiromi; Kawada, Toru; Shimizu, Shuji; Kamiya, Atsunori; Turner, Michael J.; Miyazaki, Shunichi; Sugimachi, Masaru.

In: Life Sciences, Vol. 126, 01.04.2015, p. 37-41.

Research output: Contribution to journalArticle

Yamamoto, Hiromi ; Kawada, Toru ; Shimizu, Shuji ; Kamiya, Atsunori ; Turner, Michael J. ; Miyazaki, Shunichi ; Sugimachi, Masaru. / Acute effects of intravenous nifedipine or azelnidipine on open-loop baroreflex static characteristics in rats. In: Life Sciences. 2015 ; Vol. 126. pp. 37-41.
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T1 - Acute effects of intravenous nifedipine or azelnidipine on open-loop baroreflex static characteristics in rats

AU - Yamamoto, Hiromi

AU - Kawada, Toru

AU - Shimizu, Shuji

AU - Kamiya, Atsunori

AU - Turner, Michael J.

AU - Miyazaki, Shunichi

AU - Sugimachi, Masaru

PY - 2015/4/1

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N2 - Aims To assess the acute effects of intravenous azelnidipine, a third-generation L-type calcium channel blocker, on sympathetic outflow from the central nervous system and to compare the effects of intravenous azelnidipine with those of intravenous nifedipine. Main methods In anesthetized Wistar Kyoto rats, carotid sinus baroreceptor regions were isolated. Changes in sympathetic nerve activity (SNA) and arterial pressure (AP) in response to a stepwise baroreceptor pressure input were examined before and during intravenous nifedipine or azelnidipine (for each: 100 μg/kg bolus followed by 300 μg/kg/h infusion, n = 6). Key findings Nifedipine significantly reduced the range of the AP response from 76.8 ± 7.4 to 45.4 ± 7.0 mm Hg (P < 0.01) but did not affect the range of the SNA response (from 84.4 ± 5.1 to 85.9 ± 10.2%) or the SNA maximum gain (from 2.26 ± 0.28 to 2.35 ± 0.55%/mm Hg). Similarly, azelnidipine significantly reduced the range of the AP response from 62.4 ± 3.9 to 31.4 ± 4.1 mm Hg (P < 0.01) but did not affect the range of the SNA response (from 71.2 ± 5.5 to 74.9 ± 7.2%) or the SNA maximum gain (from 1.64 ± 0.17 to 2.08 ± 0.26%/mm Hg). Significance A depressor dose of nifedipine or azelnidipine does not have an acute sympathoinhibitory effect in normotensive Wistar Kyoto rats even when the level of SNA was varied over the entire operating range of the carotid sinus baroreflex.

AB - Aims To assess the acute effects of intravenous azelnidipine, a third-generation L-type calcium channel blocker, on sympathetic outflow from the central nervous system and to compare the effects of intravenous azelnidipine with those of intravenous nifedipine. Main methods In anesthetized Wistar Kyoto rats, carotid sinus baroreceptor regions were isolated. Changes in sympathetic nerve activity (SNA) and arterial pressure (AP) in response to a stepwise baroreceptor pressure input were examined before and during intravenous nifedipine or azelnidipine (for each: 100 μg/kg bolus followed by 300 μg/kg/h infusion, n = 6). Key findings Nifedipine significantly reduced the range of the AP response from 76.8 ± 7.4 to 45.4 ± 7.0 mm Hg (P < 0.01) but did not affect the range of the SNA response (from 84.4 ± 5.1 to 85.9 ± 10.2%) or the SNA maximum gain (from 2.26 ± 0.28 to 2.35 ± 0.55%/mm Hg). Similarly, azelnidipine significantly reduced the range of the AP response from 62.4 ± 3.9 to 31.4 ± 4.1 mm Hg (P < 0.01) but did not affect the range of the SNA response (from 71.2 ± 5.5 to 74.9 ± 7.2%) or the SNA maximum gain (from 1.64 ± 0.17 to 2.08 ± 0.26%/mm Hg). Significance A depressor dose of nifedipine or azelnidipine does not have an acute sympathoinhibitory effect in normotensive Wistar Kyoto rats even when the level of SNA was varied over the entire operating range of the carotid sinus baroreflex.

KW - Azelnidipine

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KW - Open-loop system analysis

KW - Sympathetic nerve activity

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