Document Detail


Cardiac actions of central but not peripheral urotensin II are prevented by beta-adrenoceptor blockade.
MedLine Citation:
PMID:  15949643     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Urotensin II (UII) is a highly conserved peptide that has potent cardiovascular actions following central and systemic administration. To determine whether the cardiovascular actions of UII are mediated via beta-adrenoceptors, we examined the effect of intravenous (IV) propranolol on the responses to intracerebroventricular (ICV) and IV administration of UII in conscious sheep. Sheep were surgically instrumented with ICV guide tubes and flow probes or cardiac sympathetic nerve recording electrodes. ICV UII (0.2 nmol/kg over 1 h) caused prolonged increases in heart rate (HR; 33 +/- 11 beats/min; P < 0.01), dF/dt (581 +/- 83 L/min/s; P < 0.001) and cardiac output (2.3 +/- 0.4 L/min; P < 0.001), accompanied by increases in coronary (19.8 +/- 5.4 mL/min; P < 0.01), mesenteric (211 +/- 50 mL/min; P < 0.05) and iliac (162 +/- 31 mL/min; P < 0.001) blood flows and plasma glucose (7.0 +/- 2.6 mmol/L; P < 0.05). Propranolol (30 mg bolus followed by 0.5 mg/kg/h IV) prevented the cardiac responses to ICV UII and inhibited the mesenteric vasodilatation. At 2 h after ICV UII, when HR and mean arterial pressure (MAP) were increased, cardiac sympathetic nerve activity (CSNA) was unchanged and the relation between CSNA and diastolic pressure was shifted to the right (P < 0.05). The hyperglycemia following ICV UII was abolished by ganglion blockade but not propranolol. IV UII (20 nmol/kg) caused a transient increase in HR and fall in stroke volume; these effects were not blocked by propranolol. These results demonstrate that the cardiac actions of central UII depend on beta-adrenoreceptor stimulation, secondary to increased CSNA and epinephrine release, whereas the cardiac actions of systemic UII are not mediated by beta-adrenoreceptors and probably depend on a direct action of UII on the heart.
Authors:
S G Hood; A M D Watson; C N May
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Peptides     Volume:  26     ISSN:  0196-9781     ISO Abbreviation:  Peptides     Publication Date:  2005 Jul 
Date Detail:
Created Date:  2005-06-13     Completed Date:  2005-10-14     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8008690     Medline TA:  Peptides     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1248-56     Citation Subset:  IM    
Affiliation:
Howard Florey Institute, University of Melbourne, Parkville, Vic. 3010, Australia.
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MeSH Terms
Descriptor/Qualifier:
Adrenergic beta-Antagonists / pharmacology*
Animals
Female
Heart / drug effects*,  innervation
Heart Rate / drug effects
Injections, Intravenous
Injections, Intraventricular
Propranolol / pharmacology
Receptors, Adrenergic, beta / drug effects
Sheep
Sympathetic Nervous System / drug effects
Urotensins / administration & dosage*,  antagonists & inhibitors*,  pharmacology
Chemical
Reg. No./Substance:
0/Adrenergic beta-Antagonists; 0/Receptors, Adrenergic, beta; 0/Urotensins; 525-66-6/Propranolol; 9047-55-6/urotensin II

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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