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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1997-11-20
pubmed:abstractText
The effect of the atypical antidepressants mianserin, iprindole, and fluoxetine on synaptosomal calcium uptake was tested under conditions where a selective action on voltage-dependent calcium channels can be documented. Synaptosomes from rat hippocampus were incubated with 45calcium either in choline-rich medium or in depolarizing (60 mM K+) choline-rich medium, and drug effects on calcium uptake in these two conditions, as well as on the net depolarization-induced calcium uptake, were studied in the range of concentrations 0.6-200 microM. A concentration-dependent marked inhibition of uptake in depolarizing choline medium was observed for the three antidepressants, whereas only a minor degree of inhibition of uptake in resting choline medium was present at the highest drug concentration; as a result, the concentration-effect relationships exhibited a strong concentration-dependent inhibition of net depolarization-induced calcium uptake. The IC50 values, calculated by interpolation of the last three or four points of the concentration-effect relationships, were 27, 39, and 68 microM for fluoxetine, iprindole, and mianserin, respectively. Significant degrees of calcium channel inhibition are not expected at brain concentrations of mianserin and iprindole that are likely to be encountered during clinical use; however, the fluoxetine concentration-effect relationship established in the present study, coupled with the published ratio of 20:1 for brain:plasma concentrations of fluoxetine-norfluoxetine in humans, suggests that brain calcium channel function could be appreciably reduced in some patients treated with this atypical antidepressant.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0008-4212
pubmed:author
pubmed:issnType
Print
pubmed:volume
75
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
983-7
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Atypical antidepressants inhibit depolarization-induced calcium uptake in rat hippocampus synaptosomes.
pubmed:affiliation
Département de pharmacologie, Université de Montréal, QC, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't