Document Detail


Assessment of behavior during labor in rats and effect of intrathecal morphine.
MedLine Citation:
PMID:  18497609     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Efficacy of analgesics varies with the type of pain. Little is known in this regard concerning labor pain, given the ethical barriers to study in humans and the lack of surrogate animal models. To address this, the authors classified and quantified spontaneous behaviors during labor and delivery in rats and examined the effects of a known analgesic, intrathecal morphine. METHODS: Pregnant rats were video recorded for 72 h surrounding the time of anticipated labor and delivery. Specific behaviors were identified and classified into general activities, phasic stretching behaviors, and maternal attention activities. Rats received intrathecal infusion of saline or morphine, 0.035-3.5 microg/h, beginning approximately 1 day before delivery, and effects on behaviors and response to noxious heating of the paw were quantified. RESULTS: Phasic stretching behaviors occurred with high frequency before delivery of the first pup and were rare after delivery of the last pup. Intrathecal morphine at infusion rates greater than 0.035 microg/h abolished these behaviors without affecting general or maternal behaviors or the timing or duration of labor and delivery. Morphine was also antinociceptive to noxious heat, but only at infusion rates of 1.0 microg/h or higher. CONCLUSIONS: Phasic stretching behaviors are observed after distension or inflammation of pelvic viscera in rats, and similar behaviors occur during labor and delivery. Selective and dose-related blockade by intrathecal morphine of only these behaviors suggests that they reflect nociception and that this simple monitoring method can be used to study therapies for the pain of labor and delivery.
Authors:
Chuanyao Tong; Dawn R Conklin; Baogang Liu; Douglas G Ririe; James C Eisenach
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural    
Journal Detail:
Title:  Anesthesiology     Volume:  108     ISSN:  1528-1175     ISO Abbreviation:  Anesthesiology     Publication Date:  2008 Jun 
Date Detail:
Created Date:  2008-05-23     Completed Date:  2008-06-17     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  1300217     Medline TA:  Anesthesiology     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1081-6     Citation Subset:  AIM; IM    
Affiliation:
Department of Anesthesiology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1009, USA.
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MeSH Terms
Descriptor/Qualifier:
Analgesia, Obstetrical / methods
Analgesics, Opioid / administration & dosage,  pharmacology*
Animals
Behavior, Animal / drug effects*
Dose-Response Relationship, Drug
Female
Hindlimb
Hot Temperature
Injections, Spinal
Labor Pain / drug therapy*
Labor, Obstetric / drug effects*
Models, Animal*
Morphine / administration & dosage,  pharmacology*
Nesting Behavior / drug effects
Pain Measurement / drug effects
Physical Stimulation / methods
Pregnancy
Rats
Rats, Sprague-Dawley
Sodium Chloride / administration & dosage
Time Factors
Grant Support
ID/Acronym/Agency:
NS48065/NS/NINDS NIH HHS
Chemical
Reg. No./Substance:
0/Analgesics, Opioid; 57-27-2/Morphine; 7647-14-5/Sodium Chloride

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


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