| Effects of thymoxamine and its metabolites on clonidine-induced hypotension and bradycardia in rats. | |
| | |
MedLine Citation:
|
PMID: 6215903 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
Thymoxamine and deacetylthymoxamine antagonized the hypertensive response of pithed rats to noradrenaline and clonidine, probably by inhibiting vascular post-synaptic alpha-adrenoceptors. N-demethyl-deacetylthymoxamine was inactive. Clonidine-induced reduction of tachycardia caused by electrical stimulation of the cardiac sympathetic nerve in pithed rats was antagonized by phentolamine but not by prazosin, thymoxamine, deacetylthymoxamine or N-demetyldeacetylthymoxamine. This suggests that prazosin and thymoxamine and its derivatives predominantly blocked alpha 1-adrenoceptors. In pentobarbitone-anaesthetized normotensive rats, prazosin, thymoxamine and deacetylthymoxamine decreased the hypotensive effect of clonidine, but had no significant effect on clonidine-induced bradycardia. These substances antagonized clonidine-induced hypotension in rats by the probable mechanism of inhibiting central alpha 1-adrenoceptors whose characteristics are similar to peripheral receptors. These data suggest that clonidine produced a hypotensive action in pentobarbitone anaesthetized rats via alpha 1-adrenoceptors and produced bradycardia via alpha 2-adrenoceptors. |
| | |
Authors:
|
J Roquebert; P Demichel; A Malek |
Related Documents
:
|
2575523 - The alpha 2-adrenoceptor antagonists idazoxan and yohimbine can unmask the postsynaptic... 2966063 - Stimulation of growth hormone secretion by central administration of atrial natriuretic... 3345203 - Age-dependent decrease in the hepatic uptake and biliary excretion of ouabain in rats. |
Publication Detail:
|
Type: Journal Article |
Journal Detail:
|
Title: Archives internationales de pharmacodynamie et de thérapie Volume: 258 ISSN: 0003-9780 ISO Abbreviation: Arch Int Pharmacodyn Ther Publication Date: 1982 Jul |
Date Detail:
|
Created Date: 1982-12-16 Completed Date: 1982-12-16 Revised Date: 2012-01-12 |
Medline Journal Info:
|
Nlm Unique ID: 0405353 Medline TA: Arch Int Pharmacodyn Ther Country: BELGIUM |
Other Details:
|
Languages: eng Pagination: 116-27 Citation Subset: IM |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Anesthesia Animals Blood Pressure / drug effects* Bradycardia / chemically induced Clonidine / pharmacology* Heart Rate / drug effects* Hypotension / chemically induced Male Moxisylyte / pharmacology* Norepinephrine / pharmacology Prazosin / pharmacology Rats Rats, Inbred Strains Spinal Cord / physiology |
| Chemical | |
Reg. No./Substance:
|
19216-56-9/Prazosin; 4205-90-7/Clonidine; 51-41-2/Norepinephrine; 54-32-0/Moxisylyte |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Echocardiographic signs of congenital absence of the pulmonary semilunar cusps
Next Document: Autacoid and autonomic reactivity of bovine and ovine bronchus: modifications by antigenic sensitiza...