Document Detail


Physical exercise-induced cardiovascular adjustments are modulated by muscarinic cholinoceptors within the ventromedial hypothalamic nucleus.
MedLine Citation:
PMID:  19537936     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The effects of blocking ventromedial hypothalamic nucleus (VMH) muscarinic cholinoceptors on cardiovascular responses were investigated in running rats. Animals were anesthetized with pentobarbital sodium and fitted with bilateral cannulae into the VMH. After recovering from surgery, the rats were familiarized to running on a treadmill. The animals then had a polyethylene catheter implanted into the left carotid artery to measure blood pressure. Tail skin temperature (T(tail)), heart rate, and systolic, diastolic and mean arterial pressure were measured after bilateral injections of 0.2 microl of 5 x 10(-9) mol methylatropine or 0.15 M NaCl solution into the hypothalamus. Cholinergic blockade of the VMH reduced time to fatigue by 31 % and modified the temporal profile of cardiovascular and T(tail) adjustments without altering their maximal responses. Mean arterial pressure peak was achieved earlier in methylatropine-treated rats, which also showed a 2-min delay in induction of tail skin vasodilation, suggesting a higher sympathetic tonus to peripheral vessels. In conclusion, muscarinic cholinoceptors within the VMH are involved in a neuronal pathway that controls exercise-induced cardiovascular adjustments. Furthermore, blocking of cholinergic transmission increases sympathetic outflow during the initial minutes of exercise, and this higher sympathetic activity may be responsible for the decreased performance.
Authors:
S P Wanner; J B Guimarães; W Pires; R B La Guardia; A S Haibara; U Marubayashi; C C Coimbra; N R V Lima
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Publication Detail:
Type:  Journal Article     Date:  2009-06-19
Journal Detail:
Title:  Physiological research / Academia Scientiarum Bohemoslovaca     Volume:  59     ISSN:  0862-8408     ISO Abbreviation:  Physiol Res     Publication Date:  2010  
Date Detail:
Created Date:  2010-05-20     Completed Date:  2010-08-02     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9112413     Medline TA:  Physiol Res     Country:  Czech Republic    
Other Details:
Languages:  eng     Pagination:  165-75     Citation Subset:  IM    
Affiliation:
Exercise Physiology Laboratory, Department of Physical Education, School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
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MeSH Terms
Descriptor/Qualifier:
Animals
Atropine Derivatives / pharmacology
Blood Pressure / drug effects,  physiology*
Heart Rate / drug effects,  physiology*
Male
Parasympatholytics / pharmacology
Physical Conditioning, Animal / physiology*
Rats
Rats, Wistar
Receptors, Muscarinic / physiology*
Skin Temperature / drug effects,  physiology
Sympathetic Nervous System / physiology
Tail
Vasodilation / drug effects,  physiology
Ventromedial Hypothalamic Nucleus / drug effects,  physiology*
Chemical
Reg. No./Substance:
0/Atropine Derivatives; 0/Parasympatholytics; 0/Receptors, Muscarinic; 31610-87-4/methylatropine

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


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