Document Detail


Verapamil protective effect on natural and artificial magnetic field cardiovascular impact.
MedLine Citation:
PMID:  12224057     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Previously we found an opposite effect of artificial static magnetic field (SMF) and natural geomagnetic field (GMF) on arterial baroreceptors. A 0.35 T SMF increased baroreflex sensitivity (BRS), whereas GMF disturbance decreased BRS. Here, we investigated interrelated impacts on arterial baroreceptors of 0.35 T SMF, generated by Nd(2)-Fe(14)-B alloy magnets, GMF, and verapamil, a Ca(2+) channel blocking agent. We measured BRS in rabbits before and after local SMF exposure of sinocarotid baroreceptors or after simultaneous SMF and verapamil application, in conjunction with geomagnetic disturbance during actual experimental run (determined by K-index) and geomagnetic disturbance over the preceding 24 h of each experiment (A(k)-index). BRS was estimated from peak responses of mean arterial pressure (MAP) and heart rate, expressed as percentages of the resting values preceding each pair of pressure (phenylephrine) and depressor drug (nitroprusside) injections. Prior to verapamil and/or SMF application we found a significant positive correlation of K-index with MAP (t = 2.39, P =.021, n = 44), but negative with BRS (t = -4.60, P =.0003, n = 44), and found a negative correlation of A(k)-index with BRS (t = -2.7, P = 0.01, n = 44). SMF induced an increase in BRS (0.79 +/- 0.1 vs. 1.15 +/- 0.1 bpm%/mmHg%, initial value vs. SMF exposure, P <.0002, n = 26). Verapamil infusion blocked the SMF and GMF effect on BRS, indicating Ca(2+) channels as a possible site of both fields' impact. SMF and GMF probably affect baroreceptor sensory transduction, modulating baroreceptor membranes' Ca(2+) channel permeability.
Authors:
Juraj Gmitrov; Chiyoji Ohkubo
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Bioelectromagnetics     Volume:  23     ISSN:  0197-8462     ISO Abbreviation:  Bioelectromagnetics     Publication Date:  2002 Oct 
Date Detail:
Created Date:  2002-09-11     Completed Date:  2003-01-08     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  8008281     Medline TA:  Bioelectromagnetics     Country:  United States    
Other Details:
Languages:  eng     Pagination:  531-41     Citation Subset:  IM    
Copyright Information:
Copyright 2002 Wiley-Liss, Inc.
Affiliation:
Department of Physiological Hygiene, The National Institute of Public Health, Tokyo, Japan.
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MeSH Terms
Descriptor/Qualifier:
Animals
Baroreflex / drug effects*,  physiology,  radiation effects*
Blood Pressure
Carotid Sinus / physiopathology
Earth (Planet)
Heart Rate
Magnetics*
Male
Pressoreceptors / drug effects,  physiology,  radiation effects
Rabbits
Reproducibility of Results
Sensitivity and Specificity
Statistics as Topic
Verapamil / pharmacology*
Chemical
Reg. No./Substance:
52-53-9/Verapamil

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


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