Linked Life Data

10591900

Source:http://linkedlifedata.com/resource/pubmed/id/10591900

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2000-1-19
pubmed:abstractText
We studied the effects of morphine injected either systemically or into the dorsal periaqueductal gray (DPAG) or nucleus accumbens (NA) using conventional and ethological analyses of behavior of rats submitted to the elevated plus-maze test with transparent walls. Intraperitoneal morphine (0.1 mg/kg and 0.3 mg/kg) increased both standard and ethological measures, expressing general exploratory activity such as total arm entries, end-exploration, scanning, head-dipping, and rearing. Morphine 10 (7.6 microg/microl) and 30 nmol (23 microg/microl) injected into nucleus accumbens produced similar effects, which were blocked by i.p. naltrexone (2.0 mg/kg), an opioid antagonist with good affinity for mu-opioid receptors. Morphine injected into the DPAG produced either antiaversive (10 nmol) or aversive effects (30 nmol), which respectively reduced and increased entries and time spent in the open arms and behaviors associated with risk assessment (peeping out, stretched attend postures, and flat back approach). The proaversive effects were inhibited by i.p. norbinaltorphimine (2.0 mg/kg), a selective inhibitor for kappa-opioid receptors. These findings support the contention that at least some of the motivational effects of morphine may be due to activation of opioid mechanisms in nucleus accumbens, and DPAG has neural substrates for antiaversive and aversive effects of morphine. Moreover, on the basis of previous and present data obtained in this laboratory, it is suggested that stimulation of mu-opioid receptors inhibits and stimulation of kappa-receptors activates the neural substrate of aversion in the DPAG. On the other hand, the increase in exploratory behavior due to interaction of morphine with mu-opioid receptors in the nucleus accumbens may be due to the stimulation of the interface between neural substrates of motivation and motor output in this structure.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0014-4819
pubmed:author
pubmed:issnType
Print
pubmed:volume
129
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
260-8
pubmed:dateRevised
2009-11-11
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
A comparative study of the effects of morphine in the dorsal periaqueductal gray and nucleus accumbens of rats submitted to the elevated plus-maze test.
pubmed:affiliation
Laboratório de Psicobiologia, FFCLRP, campus USP, Av. Bandeirantes 3900, 14049-901, Ribeirão Preto, SP, Brazil.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't