Document Detail

pH-dependent accumulation of fentanyl, lofentanil and alfentanil by beating guinea pig atria.
MedLine Citation:
PMID:  2864047     Owner:  NLM     Status:  MEDLINE    
The influence of the pH of the incubation medium on the cellular accumulation of tritiated fentanyl, lofentanil, and alfentanil was investigated in isolated guinea pig atria. Fentanyl and lofentanil accumulated in atrial tissue up to about 30- and 50-fold, respectively. The amount of drug bound when equilibrium was attained was found to be dependent upon the pH of the medium. By plotting binding equilibria v. pH of the bath, curves were obtained which resembled titration curves. Half-maximal binding was attained at pH values close to the pKa values of fentanyl and lofentanil. Alfentanil was found to accumulate less. The uptake by the tissue was strongly proportional to the extracellular concentration. Atria equilibrated with fentanyl at pH 8.5 released the compound rapidly when exposed to a pH of 7.0, even in the continuous presence of fentanyl in the bath. The consequences of the findings for in vivo conditions are discussed with respect to a possible augmentation of the actions of fentanyl by respiratory acidosis.
H Lüllmann; B S Martins; T Peters
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Publication Detail:
Type:  In Vitro; Journal Article    
Journal Detail:
Title:  British journal of anaesthesia     Volume:  57     ISSN:  0007-0912     ISO Abbreviation:  Br J Anaesth     Publication Date:  1985 Oct 
Date Detail:
Created Date:  1985-11-19     Completed Date:  1985-11-19     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0372541     Medline TA:  Br J Anaesth     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  1012-7     Citation Subset:  IM    
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MeSH Terms
Analgesics, Opioid / metabolism*
Fentanyl / analogs & derivatives*,  metabolism*
Guinea Pigs
Heart Atria
Hydrogen-Ion Concentration
Myocardial Contraction
Myocardium / metabolism*
Time Factors
Reg. No./Substance:
0/Analgesics, Opioid; 437-38-7/Fentanyl; 60645-00-3/lofentanil; 71195-58-9/Alfentanil

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

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