Document Detail

Importance of central nervous system serotonin-1A receptors for mediating the hypotensive effect of urapidil.
MedLine Citation:
PMID:  2530339     Owner:  NLM     Status:  MEDLINE    
Urapidil is thought to lower blood pressure by both a peripheral and a central mechanism. The former effect is caused by blockade of alpha-1 adrenoceptors whereas the latter effect has been shown to occur in the medulla, specifically at the intermediate area on the ventral surface of the medulla. The receptor mediating the central effect is not the alpha-1 adrenoceptor, but has been postulated to be the serotonin (5-HT)1A receptor. To determine whether urapidil lowers blood pressure by stimulating 5-HT1A receptors at the intermediate area, we applied urapidil bilaterally (50 micrograms/side) to the intermediate area of chloralose-anesthetized cats while monitoring arterial blood pressure and heart rate. Application of urapidil caused decreases in mean blood pressure and heart rate of 66 +/- 8 mm Hg and 31 +/- 7 beats/min, respectively. Pretreatment with the 5-HT1A and 5-HT2 receptor antagonist, spiperone (30 micrograms/side), counteracted the effects of urapidil. Pretreatment with the 5-HT2 receptor antagonist, ketanserin, did not alter the hypotensive effect of urapidil. Urapidil given i.v. in a dose of 2 mg/kg decreased mean blood pressure and heart rate by 53 +/- 6 mm Hg and 10 +/- 2 beats/min, respectively. At the peak of the i.v. response, spiperone (30 micrograms/side) was applied to the intermediate area and increased mean blood pressure and heart rate by 52 +/- 6 mm Hg and 20 +/- 4 beats/min, respectively, thus effectively reversing the effects of i.v. urapidil.(ABSTRACT TRUNCATED AT 250 WORDS)
A K Mandal; K J Kellar; E Friedman; S V Pineo; P Hamosh; R A Gillis
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of pharmacology and experimental therapeutics     Volume:  251     ISSN:  0022-3565     ISO Abbreviation:  J. Pharmacol. Exp. Ther.     Publication Date:  1989 Nov 
Date Detail:
Created Date:  1989-12-21     Completed Date:  1989-12-21     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0376362     Medline TA:  J Pharmacol Exp Ther     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  563-70     Citation Subset:  IM    
Department of Pharmacology, Georgetown University School of Medicine, Washington, District of Columbia.
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MeSH Terms
Antihypertensive Agents / pharmacology*
Blood Pressure / drug effects
Heart Rate / drug effects
Medulla Oblongata / drug effects*
Piperazines / pharmacology*
Prazosin / pharmacology
Receptors, Serotonin / drug effects*
Respiration / drug effects
Spiperone / pharmacology
Tetrahydronaphthalenes / pharmacology
Reg. No./Substance:
0/Antihypertensive Agents; 0/Piperazines; 0/Receptors, Serotonin; 0/Tetrahydronaphthalenes; 19216-56-9/Prazosin; 34661-75-1/urapidil; 749-02-0/Spiperone; 78950-78-4/8-Hydroxy-2-(di-n-propylamino)tetralin

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

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