Document Detail

Mechanism of the reflex inhibition of heart rate elicited by acupuncture-like stimulation in anesthetized rats.
MedLine Citation:
PMID:  18693143     Owner:  NLM     Status:  MEDLINE    
Acupuncture or acupuncture-like stimulation applied to different body areas can modify autonomic nerve activity to various organs, including gut, bladder, adrenal medulla, and the heart. We studied the reflex bradycardia in response to insertion into the skin and underlying muscles and twisting of an acupuncture needle in pentobarbital-anesthetized rats. We found that acupuncture-like stimulation of forelimb, hindlimb, chest, and abdomen all produced significant heart rate decreases. Rate minima were reached at the end of the 60-second stimulation episode and significant bradycardia persisted for about 40 s after stimulation ended. Heart rate decreases were paralleled by decreases in cardiac sympathetic nerve activity, and could be produced by electrical stimulation of group IV muscle afferent fibers (tibial nerve). Electrical stimulation of the tibial nerve at rates as low as 0.1-2 Hz was effective for eliciting heart rate decreases. Nerve fiber groups were defined by stimulation of and recording from tibial nerve. Activation of groups I, II, or III fiber was ineffective for eliciting the reflex bradycardia. Sympathectomy, high spinal transection, or infusion of the GABA(A) receptor antagonist, bicuculline, into the cisterna magna were all effective for disrupting the reflex bradycardia. Vagotomy and opioid receptor blockade were ineffective for disrupting the reflex pathway. We conclude that the reflex pathway to decrease heart rate by acupuncture-like stimulation consists of mainly group IV muscle afferent fibers whose activity (even very low rate of activity) leads to the activation of GABA-ergic neurons in the brainstem and an inhibition of sympathetic outflow to the heart.
Sae Uchida; Fusako Kagitani; Harumi Hotta
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Publication Detail:
Type:  Journal Article     Date:  2008-08-06
Journal Detail:
Title:  Autonomic neuroscience : basic & clinical     Volume:  143     ISSN:  1872-7484     ISO Abbreviation:  Auton Neurosci     Publication Date:  2008 Dec 
Date Detail:
Created Date:  2008-11-25     Completed Date:  2009-02-03     Revised Date:  2009-08-12    
Medline Journal Info:
Nlm Unique ID:  100909359     Medline TA:  Auton Neurosci     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  12-9     Citation Subset:  IM    
Department of the Autonomic Nervous System, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo 173-0015, Japan.
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MeSH Terms
Acupuncture Points
Afferent Pathways / drug effects,  physiology*
Bicuculline / administration & dosage,  pharmacology
Bradycardia / physiopathology
Electric Stimulation / methods
GABA Antagonists / administration & dosage,  pharmacology
Heart Rate / drug effects,  physiology
Injections, Intravenous
Muscle, Skeletal / drug effects,  innervation,  physiology
Naloxone / administration & dosage,  pharmacology
Narcotic Antagonists / administration & dosage,  pharmacology
Neural Inhibition / drug effects,  physiology*
Neurons / physiology
Rats, Wistar
Reflex / drug effects,  physiology*
Skin / innervation
Sympathetic Nervous System / drug effects,  physiology*
Tibial Nerve / physiology
Vagotomy / methods
Reg. No./Substance:
0/GABA Antagonists; 0/Narcotic Antagonists; 465-65-6/Naloxone; 485-49-4/Bicuculline

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

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