Document Detail

Stereoselective effects of central alpha 2-adrenergic agonist medetomidine on in vivo catechol activity in the rat rostral ventrolateral medulla (RVLM).
MedLine Citation:
PMID:  1360311     Owner:  NLM     Status:  MEDLINE    
The stereoselective central effects of a novel, highly potent and selective alpha 2-agonist medetomidine on adrenergic neuronal activity, reflected by changes in catechol oxidation current, in the rostral ventrolateral medulla of the halothane-anesthetized rat were examined using in vivo differential normal pulse voltammetry. Dexmedetomidine, the active isomer, significantly decreased catechol oxidation current to 33.4 +/- 4.5% of baseline when given centrally (1 microgram, i.c.v.) and to 10.3 +/- 3.9% of baseline when given systemically (50 micrograms/kg, i.v.). Dexmedetomidine also significantly reduced mean arterial blood pressure by 19.9% following central administration but significantly increased mean arterial blood pressure by 59.9% following systemic administration. Levomedetomidine, the inactive isomer, had no effect on catechol oxidation current or blood pressure. The depressant effects of dexmedetomidine on catechol oxidation current were reversed by the selective alpha 2-adrenoceptor antagonist atipamezole (2 micrograms, i.c.v. or 200 micrograms/kg, i.v.). The results of the present study demonstrate, to our knowledge, for the first time the central stereoselective effects of medetomidine and antagonism by atipamezole on rostral ventrolateral medulla activity in the anesthetized rat.
M Hong; B Milne; C Loomis; K Jhamandas
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Brain research     Volume:  592     ISSN:  0006-8993     ISO Abbreviation:  Brain Res.     Publication Date:  1992 Oct 
Date Detail:
Created Date:  1993-01-06     Completed Date:  1993-01-06     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0045503     Medline TA:  Brain Res     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  163-9     Citation Subset:  IM    
Department of Pharmacology and Toxicology, Faculty of Medicine, Queen's University, Kingston, Ontario, Canada.
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MeSH Terms
Adrenergic alpha-Agonists / pharmacology*
Brain / drug effects*
Catechols / metabolism*
Imidazoles / pharmacology*
Injections, Intravenous
Injections, Intraventricular
Medulla Oblongata / metabolism*
Oxidation-Reduction / drug effects
Pargyline / pharmacology
Rats, Sprague-Dawley
Reg. No./Substance:
0/Adrenergic alpha-Agonists; 0/Catechols; 0/Imidazoles; 555-57-7/Pargyline; 86347-14-0/Medetomidine

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