Document Detail

Relative affinities of S 3341 and clonidine for the alpha 2- and alpha 2-adrenoceptors of the rat brain (author's transl)
MedLine Citation:
PMID:  6116834     Owner:  NLM     Status:  MEDLINE    
1. 3H-prazosin binds to brain alpha 1-adrenoceptors with high affinity (K(D) 25 degrees C approximately or equal to 1 nM). The number of binding sites in different regions of the brain varied from 44-114 fmoles/mg of protein: striatum = medulla oblongata less than hypothalamus less than cortex. 2. 3H-p-aminoclonidine labels brain alpha 1-adrenoceptors. Its binding capacity (66-209 fmoles/mg prot). is higher in the hypothalamus greater than cortex greater than striatum greater than or equal to medulla oblongata. Its affinity varies from one region to another (0.85 mM in cortex, 3.0 nM in hypothalamus). 3. S 3341 in a potent inhibitor of 3H-p-aminoclonidine like clonidine and a weak inhibitor of 3H-prazosin. 4. Comparison of the inhibitory effect of S 3341 and clonidine on the binding of 3H-prazosin and 3H-aminoclonidine indicates that S 3341 is 2-3 times more specific for alpha 2-adrenoceptors than clonidine. 5. Inhibition constants of S 3341 and clonidine (K1) are not identical in various brain regions but clonidine and S 3341 constants vary in parallel.
P Guicheney; J P Dausse; P Meyer
Publication Detail:
Type:  English Abstract; In Vitro; Journal Article    
Journal Detail:
Title:  Journal de pharmacologie     Volume:  12     ISSN:  0021-793X     ISO Abbreviation:  J Pharmacol     Publication Date:    1981 Jul-Sep
Date Detail:
Created Date:  1981-12-21     Completed Date:  1981-12-21     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  1247760     Medline TA:  J Pharmacol     Country:  FRANCE    
Other Details:
Languages:  fre     Pagination:  255-62     Citation Subset:  IM    
Vernacular Title:
Affinités respectives du S3341 et de la clonidine pour les recepteurs adrénergiques alpha1 et alpha 2 du cerveau du rat.
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MeSH Terms
Adrenergic alpha-Agonists / metabolism*
Binding, Competitive
Brain / metabolism*
Clonidine / metabolism*
Oxazoles / metabolism*
Rats, Inbred Strains
Receptors, Adrenergic / metabolism*
Receptors, Adrenergic, alpha / metabolism*
Reg. No./Substance:
0/Adrenergic alpha-Agonists; 0/Oxazoles; 0/Receptors, Adrenergic; 0/Receptors, Adrenergic, alpha; 4205-90-7/Clonidine; 54187-04-1/rilmenidine

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