Document Detail


Central pathway for spontaneous and prostaglandin E2-evoked cutaneous vasoconstriction.
MedLine Citation:
PMID:  18463193     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A reduction of heat loss to the environment through increased cutaneous vasoconstrictor (CVC) sympathetic outflow contributes to elevated body temperature during fever. We determined the role of neurons in the dorsomedial hypothalamus (DMH) in increases in CVC sympathetic tone evoked by PGE2 into the preoptic area (POA) in chloralose/urethane-anesthetized rats. The frequency of axonal action potentials of CVC sympathetic ganglion cells recorded from the surface of the tail artery was increased by 1.8 Hz following nanoinjections of bicuculline (50 pmol) into the DMH. PGE2 nanoinjection into the POA elicited a similar excitation of tail CVC neurons (+2.1 Hz). Subsequent to PGE2 into the POA, muscimol (400 pmol/side) into the DMH did not alter the activity of tail CVC neurons. Inhibition of neurons in the rostral raphé pallidus (rRPa) eliminated the spontaneous discharge of tail CVC neurons but only reduced the PGE2-evoked activity. Residual activity was abolished by subsequent muscimol into the rostral ventrolateral medulla. Transections through the neuraxis caudal to the POA increased the activity of tail CVC neurons, which were sustained through transections caudal to DMH. We conclude that while activation of neurons in the DMH is sufficient to activate tail CVC neurons, it is not necessary for their PGE2-evoked activity. These results support a CVC component of increased core temperature elicited by PGE2 in POA that arises from relief of a tonic inhibition from neurons in POA of CVC sympathetic premotor neurons in rRPa and is dependent on the excitation of CVC premotor neurons from a site caudal to DMH.
Authors:
Joseph A Rathner; Christopher J Madden; Shaun F Morrison
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2008-05-07
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  295     ISSN:  0363-6119     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2008 Jul 
Date Detail:
Created Date:  2008-07-10     Completed Date:  2008-09-03     Revised Date:  2013-06-05    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  R343-54     Citation Subset:  IM    
Affiliation:
Neurological Sciences Institute, Oregon Health and Science University, Beaverton, Oregon, USA.
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MeSH Terms
Descriptor/Qualifier:
Adipose Tissue, Brown / physiology
Animals
Bicuculline / pharmacology
Central Nervous System / physiology*
Dinoprostone / administration & dosage,  pharmacology*
GABA Antagonists / pharmacology
Male
Neurons / drug effects,  physiology
Oxytocics / administration & dosage,  pharmacology
Rats
Skin / blood supply*,  innervation
Sympathetic Nervous System / physiology
Vasoconstriction / drug effects,  physiology*
Grant Support
ID/Acronym/Agency:
NS-40987/NS/NINDS NIH HHS; R01 NS040987-06/NS/NINDS NIH HHS; R01 NS040987-07/NS/NINDS NIH HHS; R01 NS040987-08/NS/NINDS NIH HHS
Chemical
Reg. No./Substance:
0/GABA Antagonists; 0/Oxytocics; 363-24-6/Dinoprostone; 485-49-4/Bicuculline
Comments/Corrections

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