Document Detail


Diazepam does not improve the mechanical performance of rat cardiac papillary muscle exposed to chloroquine in vitro.
MedLine Citation:
PMID:  2808897     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Diazepam has been reported to decrease the cardiac toxicity of chloroquine but the precise mechanism involved remains unknown. Left ventricular papillary muscles from adult Wistar rats were exposed to 10(-4) M chloroquine and assigned to three groups: group I (n = 10) exposed to chloroquine alone; group II (n = 8) exposed to chloroquine and 10(-5) M diazepam; group III (n = 8) exposed to chloroquine and 10(-4) M diazepam. The main mechanical parameters measured were: maximum unloaded shortening velocity (Vmax), maximum lengthening velocity (maxVr), active force normalized per cross-sectional area (AF/s), contraction-relaxation coupling under low load (R1), load sensitivity of relaxation (Isot.A/Isom.A), and peak power output (Emax) determined from Hill's equation of the force-velocity curve. Data are expressed as mean percent of control values +/- SD, for groups I, II, III respectively. No differences between groups I, II, and III were noted for Vmax (87 +/- 13, 82 +/- 9, 86 +/- 7), maxVr (47 +/- 6, 48 +/- 11, 52 +/- 11), AF/s (87 +/- 16, 91 +/- 10, 83 +/- 11), Isot. A/Isom. A (113 +/- 9, 108 +/- 3, 109 +/- 7), or Emax (75 +/- 10, 81 +/- 12, 72 +/- 16). Chloroquine was shown to be a negative inotropic agent since it decreased Vmax, AF/s and Emax, but diazepam did not restore the intrinsic mechanical performance of rat cardiac papillary muscle exposed to chloroquine, therefore 1) the protective cardiovascular effects of diazepam in chloroquine poisoning are not related to an improvement in intrinsic cardiac mechanical properties; 2) inotropic agents are therefore necessary in combination with diazepam for the treatment of severe chloroquine poisoning.
Authors:
B Riou; Y Lecarpentier; P Barriot; P Viars
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Intensive care medicine     Volume:  15     ISSN:  0342-4642     ISO Abbreviation:  Intensive Care Med     Publication Date:  1989  
Date Detail:
Created Date:  1989-11-29     Completed Date:  1989-11-29     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7704851     Medline TA:  Intensive Care Med     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  390-5     Citation Subset:  IM    
Affiliation:
Institut National de la Santé et de la Recherche Médicale, Unité 275, LOA-ENSTA-Ecole Polytechnique, Palaiseau, France.
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MeSH Terms
Descriptor/Qualifier:
Animals
Chloroquine / antagonists & inhibitors*,  toxicity
Diazepam / pharmacology*
Male
Muscle, Smooth, Vascular / drug effects
Myocardial Contraction / drug effects
Papillary Muscles / drug effects*
Rats
Rats, Inbred Strains
Chemical
Reg. No./Substance:
439-14-5/Diazepam; 54-05-7/Chloroquine

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


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