Document Detail


The medullary dorsal horn: a target for the expression of opiate effects on the perceived intensity of noxious heat.
MedLine Citation:
PMID:  3760950     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We examined the effects of morphine microinjected into the medullary dorsal horn (MDH) on the ability of monkeys to detect temperature increases in the noxious heat range. Behavioral detection latency and the percentage of correct detections were used as measures of the perceived intensity of noxious heat stimuli. Three monkeys were trained to detect a change (T2) of 0.4, 0.6, or 1.0 degrees C from a previous noxious heat level of 46 degrees C (T1). Effects on attentional, motivational, and motoric aspects of the monkeys' behavior were assessed by having them detect innocuous cooling and visual stimuli in tasks of similar difficulty. Morphine (1, 3, and 10 micrograms) microinjected into the MDH produced a dose-dependent and stimulus-intensity-dependent increase in the latency to detection of the T2 stimuli. These effects were opiate receptor-mediated since they were antagonized by systemically administered naloxone (0.5 mg/kg, i.m.) given 40 min after the microinjection of morphine. There were no effects of morphine on the behavioral detection latencies to the innocuous cooling and visual stimuli, indicating that the effects of morphine were modality-specific and independent of changes in motivation, attention, or motoric ability. These data demonstrate a pharmacologically specific effect of opiates on the perceived intensity of noxious heat stimuli at the earliest central relay pathway transmitting noxious information.
Authors:
J L Oliveras; W Maixner; R Dubner; M C Bushnell; D R Kenshalo; G H Duncan; D A Thomas; R Bates
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of neuroscience : the official journal of the Society for Neuroscience     Volume:  6     ISSN:  0270-6474     ISO Abbreviation:  J. Neurosci.     Publication Date:  1986 Oct 
Date Detail:
Created Date:  1986-11-12     Completed Date:  1986-11-12     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  8102140     Medline TA:  J Neurosci     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  3086-93     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Behavior, Animal / drug effects
Dose-Response Relationship, Drug
Macaca fascicularis
Macaca mulatta
Medulla Oblongata / physiology*
Microinjections
Morphine / pharmacology
Naloxone / pharmacology
Narcotics / pharmacology*
Pruritus / chemically induced,  physiopathology
Spinal Cord / physiology*
Temperature Sense / drug effects*
Chemical
Reg. No./Substance:
0/Narcotics; 465-65-6/Naloxone; 57-27-2/Morphine

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


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