Linked Life Data

2939697

Source:http://linkedlifedata.com/resource/pubmed/id/2939697

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1986-5-30
pubmed:abstractText
The localization of opioid peptides in the rat hippocampal formation and the epileptogenic action of beta-endorphin and certain enkephalin analogues have led to speculations that opioids may play a role in limbic seizures. These immunochemical and electroencephalographic data are compatible with single-unit electrophysiological studies showing predominant excitations of hippocampal pyramidal neurons in CA1 and CA3 fields produced by iontophoresis of endorphins or enkephalins. These excitations are naloxone sensitive and appear to arise from a disinhibitory mechanism due to inhibition of inhibitory interneurons. Thus, intracellular recordings in in vitro preparations of hippocampus usually show opioid-induced reduction of inhibitory postsynaptic potentials. However, more recent studies suggest that a major opioid-containing pathway in the hippocampus, the mossy fiber projection from the dentate gyrus to CA3 pyramidal neurons, contains more pro-dynorphin-derived peptides than pro-enkephalin. Intracerebroventricular dynorphin does not induce epileptiform activity in the rat, and single-unit and field-potential studies show mixed effects on CA3 neuronal excitability, with more inhibitory responses than are seen with the enkephalins. Selective inactivation of mu opioid receptors reveals that dynorphin, which was previously shown to express specificity for kappa receptors, can act on delta receptors in CA1. Furthermore, a specific kappa agonist, U50,488H, has inhibitory actions when applied directly to CA3 neurons. These data suggest the presence of multiple opioid receptor types in the hippocampus. These multiple receptors may point to heterogeneous functions of the different families of opioid peptides in various regions of the hippocampus, and could explain the divergent effects reported for the various opioids and naloxone to promote or prevent paroxysmal activity.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0091-3952
pubmed:author
pubmed:issnType
Print
pubmed:volume
44
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
501-12
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1986
pubmed:articleTitle
Opioid peptides and epileptogenesis in the limbic system: cellular mechanisms.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Review, Research Support, Non-U.S. Gov't