Document Detail

Estrogen attenuates antinociception produced by stimulation of Kölliker-Fuse nucleus in the rat.
MedLine Citation:
PMID:  15579177     Owner:  NLM     Status:  MEDLINE    
This is the first demonstration of sex-related differences in the alpha2-adrenoceptor-mediated antinociceptive effects produced by stimulation of an endogenous noradrenergic pathway. Electrical or chemical (substance P) stimulation of Kölliker-Fuse nucleus (KF, A7) is known to produce antinociception mediated by alpha2-adrenoceptors in the spinal cord. KF stimulation has also been shown to inhibit the responses of nociceptive neurons in the dorsal horn of the medulla and the spinal cord. We investigated whether KF stimulation produces sex-specific modulation of trigeminal nociception. The N-methyl-D-aspartic acid (NMDA)-induced nociceptive behavior was employed as an index of nociception. Microinjection of NMDA (2 nmol/10 microL) in the trigeminal region produced nociceptive scratching behavior that was confined to the orofacial region. Male and ovariectomized (OVX) Sprague-Dawley rats were implanted with a guide cannula dorsal to the KF nucleus and a PE-10 cannula in the trigeminal region dorsal to obex. Nociceptive testing was conducted after 5-7 days of recovery. A group of ovariectomized rats (OVX+E) was treated with estradiol benzoate 48 h prior to nociceptive testing. There were no significant differences in the number of NMDA-induced scratches or duration between the male, OVX and OVX+E groups. Microinjection of substance P (3.7 pmol/0.5 microL) in the KF significantly reduced the number of NMDA-induced scratches and their duration in male and OVX groups; these were restored to control levels by yohimbine (30 microg/15 microL), an alpha2-adrenoceptor antagonist. However, KF stimulation failed to inhibit the NMDA-induced scratching behavior in the OVX+E group. We conclude that stimulation of KF produces estrogen-dependent modulation of nociception.
S Nag; S S Mokha
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The European journal of neuroscience     Volume:  20     ISSN:  0953-816X     ISO Abbreviation:  Eur. J. Neurosci.     Publication Date:  2004 Dec 
Date Detail:
Created Date:  2004-12-06     Completed Date:  2005-02-28     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  8918110     Medline TA:  Eur J Neurosci     Country:  France    
Other Details:
Languages:  eng     Pagination:  3203-7     Citation Subset:  IM    
Department of Physiology, Meharry Medical College, 1005 D.B. Todd Blvd., Nashville, TN-37208, USA.
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MeSH Terms
Adrenergic alpha-Antagonists / pharmacology
Behavior, Animal
Dioxanes / pharmacology
Drug Interactions
Estradiol / analogs & derivatives*,  pharmacology*
N-Methylaspartate / pharmacology
Nociceptors / drug effects*,  physiology*
Ovariectomy / methods
Pons / drug effects,  physiology*
Rats, Sprague-Dawley
Sex Factors
Substance P / pharmacology
Trigeminal Nuclei / drug effects
Yohimbine / pharmacology
Grant Support
Reg. No./Substance:
0/Adrenergic alpha-Antagonists; 0/Dioxanes; 146-48-5/Yohimbine; 33507-63-0/Substance P; 50-28-2/Estradiol; 50-50-0/estradiol 3-benzoate; 613-67-2/(2-(2',6'-dimethoxy)phenoxyethylamino)methylbenzo-1,4-dioxane; 6384-92-5/N-Methylaspartate

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

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