Document Detail

Voiding effects mediated by α2-adrenoceptors in the anaesthetized male rat.
MedLine Citation:
PMID:  20151962     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: To study the role of α(2)-adrenoceptors (α(2)-AR) in micturition of anaesthetized male rats, with specific focus on the effects on the electrical activity (by electromyography, EMG) of the rhabdosphincter, and actual urinary flow rate, as the effects mediated by α(2)-ARs on sphincter activity and urethral pressures have not been established.
MATERIALS AND METHODS: Adult anaesthetized male Noble rats were used; intravesical pressure, rhabdosphincter EMG and urinary flow rate from the distal urethra were recorded. After baseline recordings, an α(2)-AR agonist (dexmedetomidine, DEX) or α(2)-AR antagonist (atipamezole), were injected intravenously.
RESULTS: DEX treatment significantly decreased the maximum bladder pressure and urinary flow rate, and the amplitude of rhabdosphincter EMG was significantly reduced. Intraluminal pressure high-frequency oscillations, usually observed during rat voiding were abolished. The effects of DEX were fully reversed within 31 min. Atipamezole treatment significantly increased actual urinary flow rates and rhabdosphincter EMG amplitude, but the number of times flow was interrupted was increased during the voiding cycle, leading to increased overall micturition time.
CONCLUSION: Stimulation and blockade of α(2)-ARs have a significant effect on lower urinary tract function. If the data from this rat model are also valid in humans, a study of the effects of atipamezole on urethral sphincter activity and urethral pressures in humans would be of interest, and might show therapeutic potential of the drug.
Tomi Streng; Risto Santti; Karl-Erik Andersson
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  BJU international     Volume:  106     ISSN:  1464-410X     ISO Abbreviation:  BJU Int.     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-10-27     Completed Date:  2011-01-04     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100886721     Medline TA:  BJU Int     Country:  England    
Other Details:
Languages:  eng     Pagination:  1546-9     Citation Subset:  IM    
Copyright Information:
Department of Pharmacology, Drug Development and Therapeutics, and Turku Centre for Disease Modelling, Institute of Biomedicine, University of Turku, Turku, Finland.
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MeSH Terms
Adrenergic alpha-2 Receptor Agonists / pharmacology*
Adrenergic alpha-2 Receptor Antagonists / pharmacology*
Dexmedetomidine / pharmacology*
Imidazoles / pharmacology*
Urinary Tract / drug effects
Urination / drug effects*,  physiology
Urodynamics / drug effects*,  physiology
Reg. No./Substance:
0/Adrenergic alpha-2 Receptor Agonists; 0/Adrenergic alpha-2 Receptor Antagonists; 0/Imidazoles; 104054-27-5/atipamezole; 113775-47-6/Dexmedetomidine

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