Document Detail


Electrical stimulation releases 3H-betaxolol from rat atrial slices: possible role of noradrenergic nerves.
MedLine Citation:
PMID:  2872597     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Under in vitro conditions, 3H-betaxolol was accumulated in rat atrial slices, reaching a tissue-medium ratio of 12.3 +/- 1.8 ml/g. This process was temperature-dependent, but ouabain-resistant. 3H-Betaxolol accumulated in atrial slices was subsequently released by electrical stimulation. The electrically-evoked release of 3H-betaxolol was abolished in the absence of calcium, and reduced in the presence of bretylium 10 microM. After surgical sympathetic denervation by stellate ganglionectomy there was a marked reduction in the endogenous content of noradrenaline and in the retention of 3H-noradrenaline in atrial slices. The concomitant decrease in the amount of 3H-noradrenaline released by electrical stimulation following denervation was modest, although statistically significant. Following sympathetic denervation, the tissue retention of 3H-betaxolol was not significantly affected, but the release of 3H-betaxolol by electrical stimulation was considerably reduced. After pretreatment with reserpine the amount of radioactivity released by electrical stimulation from slices labelled with 3H-betaxolol or 3H-noradrenaline was markedly reduced. The tissue retention of 3H-noradrenaline was reduced to a larger extent than that of 3H-betaxolol following the administration of reserpine. The simultaneous release of noradrenaline and betaxolol by nerve stimulation observed under our experimental conditions may represent a mechanism through which betaxolol can reach selectively the postsynaptic beta 1-adrenoceptors and reinforce beta-adrenoceptor blockade in the heart.
Authors:
P Petruzzo; S Arbilla; J Allen; S Z Langer
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Publication Detail:
Type:  In Vitro; Journal Article    
Journal Detail:
Title:  Naunyn-Schmiedeberg's archives of pharmacology     Volume:  332     ISSN:  0028-1298     ISO Abbreviation:  Naunyn Schmiedebergs Arch. Pharmacol.     Publication Date:  1986 Mar 
Date Detail:
Created Date:  1986-06-27     Completed Date:  1986-06-27     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0326264     Medline TA:  Naunyn Schmiedebergs Arch Pharmacol     Country:  GERMANY, WEST    
Other Details:
Languages:  eng     Pagination:  253-7     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Adrenergic beta-Antagonists / metabolism*
Animals
Betaxolol
Calcium / physiology
Electric Stimulation
Male
Myocardium / metabolism*
Neurons / physiology*
Propanolamines / metabolism*
Rats
Rats, Inbred Strains
Stellate Ganglion / metabolism
Sympathectomy
Sympathetic Nervous System / physiology*
Chemical
Reg. No./Substance:
0/Adrenergic beta-Antagonists; 0/Propanolamines; 63659-18-7/Betaxolol; 7440-70-2/Calcium

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


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