Document Detail


Vasopressin V2 receptor enhances gain of baroreflex in conscious spontaneously hypertensive rats.
MedLine Citation:
PMID:  10070150     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The aim of the present study was to determine the receptor subtype involved in arginine vasopressin (AVP)-induced modulation of baroreflex function in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats using novel nonpeptide AVP V1- and V2-receptor antagonists. Baroreceptor heart rate (HR) reflex was investigated in both SHR and WKY rats which were intravenously administered the selective V1- and V2-receptor antagonists OPC-21268 and OPC-31260, respectively. Baroreflex function was assessed by obtaining alternate pressor and depressor responses to phenylephrine and sodium nitroprusside, respectively, to construct baroreflex curves. In both SHR and WKY rats baroreflex activity was tested before and after intravenous administration of vehicle (20% DMSO), OPC-21268 (10 mg/kg), and OPC-31260 (1 and 10 mg/kg). Vehicle did not significantly alter basal mean arterial pressure (MAP) and HR values or baroreflex function in SHR or WKY rats. The V1-receptor antagonist had no significant effect on resting MAP or HR values or on baroreflex parameters in both groups of rats, although this dose was shown to significantly inhibit the pressor response to AVP (5 ng iv; ANOVA, P < 0.05). In SHR but not WKY rats the V2-receptor antagonist significantly attenuated the gain (or slope) of the baroreflex curve (to 73 +/- 3 and 79 +/- 7% of control for 1 and 10 mg/kg, respectively), although AVP-induced pressor responses were also attenuated with the higher dose of the V2-receptor antagonist. These findings suggest that AVP tonically enhances baroreflex function through a V2 receptor in the SHR.
Authors:
D B Sampey; L M Burrell; R E Widdop
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of physiology     Volume:  276     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1999 Mar 
Date Detail:
Created Date:  1999-04-15     Completed Date:  1999-04-15     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  R872-9     Citation Subset:  IM    
Affiliation:
Department of Pharmacology, Monash University, Clayton, Victoria 3168, Australia.
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MeSH Terms
Descriptor/Qualifier:
Animals
Baroreflex / drug effects,  physiology*
Benzazepines / pharmacology
Blood Pressure / drug effects
Heart Rate / drug effects,  physiology
Injections, Intravenous
Male
Piperidines / pharmacology
Quinolones / pharmacology
Rats
Rats, Inbred SHR / physiology*
Rats, Inbred WKY / physiology
Receptors, Vasopressin / antagonists & inhibitors,  physiology*
Chemical
Reg. No./Substance:
0/Benzazepines; 0/Piperidines; 0/Quinolones; 0/Receptors, Vasopressin; 131631-89-5/OPC 21268; 137975-06-5/OPC 31260

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


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