Direct versus indirect pressor and vasoconstrictor actions of angiotensin in conscious dogs

Alan M. Fujii, Stephen F. Vatner

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

To determine the importance of the direct and the indirect pressor and vasoconstrictor actions of angiotensin II (ANG II), experiments were conducted in conscious dogs 2 to 8 weeks after instrumentation with aortic catheters and aortic electromagnetic flow probes to measure arterial pressure and cardiac output. Total peripheral resistance was calculated by an on-line digital computer. Pretreatment with propranolol eliminated complicating inotropic effects of norepinephrine, released by the indirect actions of ANG II, The pressor and vasoconstrictor responses after gangl ionic blockade, in either the presence or absence of arterial baroreceptor nerves, were considered to be the direct effects of ANG II, In conscious dogs, systemically administered ANG II (32 ng/kg bolus) increased mean arterial pressure by 38 ± 3 mm Hg, total peripheral resistance by 37 ± 2 mm Hg/L/minute, and decreased heart rate by 15 ± 2 beats/minute. After arterial baroreceptor denervation, administration of ANG II increased mean arterial pressure by 88 ± 7 mm Hg, total peripheral resistance by 54 ± 4 mm Hg/L/minute, and heart rate by 12 ± 2 beats/minute. After arterial baroreceptor denervation and ganglionic blockade with hexamethonium, administration of ANG II increased mean arterial pressure by 53 ± 8 mm Hg, total peripheral resistance by 27 ± 3 mm Hg/L/minute, and left heart rate unchanged. These results indicate that in the conscious dog without baroreflex buffering nearly one-half of the pressor and vasoconstrictor actions of angiotensin are not direct, but are mediated by the autonomic nervous system.

Original languageEnglish (US)
Pages (from-to)253-261
Number of pages9
JournalHypertension
Volume7
Issue number2
DOIs
StatePublished - Mar 1985

Fingerprint

Angiotensins
Vasoconstrictor Agents
Angiotensin II
Dogs
Vascular Resistance
Pressoreceptors
Arterial Pressure
Heart Rate
Denervation
Hexamethonium
Baroreflex
Electromagnetic Phenomena
Autonomic Nervous System
Propranolol
Cardiac Output
Norepinephrine
Catheters

All Science Journal Classification (ASJC) codes

  • Internal Medicine

Keywords

  • Angiotensin II
  • Arterial baroreceptor denervation
  • Autonomic and sympathetic nervous system
  • Cardiac output
  • Ganglionic blockade

Cite this

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abstract = "To determine the importance of the direct and the indirect pressor and vasoconstrictor actions of angiotensin II (ANG II), experiments were conducted in conscious dogs 2 to 8 weeks after instrumentation with aortic catheters and aortic electromagnetic flow probes to measure arterial pressure and cardiac output. Total peripheral resistance was calculated by an on-line digital computer. Pretreatment with propranolol eliminated complicating inotropic effects of norepinephrine, released by the indirect actions of ANG II, The pressor and vasoconstrictor responses after gangl ionic blockade, in either the presence or absence of arterial baroreceptor nerves, were considered to be the direct effects of ANG II, In conscious dogs, systemically administered ANG II (32 ng/kg bolus) increased mean arterial pressure by 38 ± 3 mm Hg, total peripheral resistance by 37 ± 2 mm Hg/L/minute, and decreased heart rate by 15 ± 2 beats/minute. After arterial baroreceptor denervation, administration of ANG II increased mean arterial pressure by 88 ± 7 mm Hg, total peripheral resistance by 54 ± 4 mm Hg/L/minute, and heart rate by 12 ± 2 beats/minute. After arterial baroreceptor denervation and ganglionic blockade with hexamethonium, administration of ANG II increased mean arterial pressure by 53 ± 8 mm Hg, total peripheral resistance by 27 ± 3 mm Hg/L/minute, and left heart rate unchanged. These results indicate that in the conscious dog without baroreflex buffering nearly one-half of the pressor and vasoconstrictor actions of angiotensin are not direct, but are mediated by the autonomic nervous system.",
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Direct versus indirect pressor and vasoconstrictor actions of angiotensin in conscious dogs. / Fujii, Alan M.; Vatner, Stephen F.

In: Hypertension, Vol. 7, No. 2, 03.1985, p. 253-261.

Research output: Contribution to journalArticle

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