Linked Life Data

7971137

Source:http://linkedlifedata.com/resource/pubmed/id/7971137

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5-6
pubmed:dateCreated
1994-12-7
pubmed:abstractText
We used whole-cell voltage clamp to compare the modulation of calcium current density (ICa, picoampere per picofarad) of freshly isolated, adult and newborn rabbit heart in response to intracellular application of microcystin and okadaic acid, both of which block phosphatase activity of phosphatase type 1 and 2A. Newborn cells showed a much larger response to the intracellular application of either microcystin or okadaic acid than did adult cells. In newborn cells, the application of microcystin produced an increase in ICa which appeared to maximize ICa, as shown by the rise in ICa to levels which could be reached by application of 10 microM forskolin or by the intracellular application of 200 microM 3',5'-cyclic adenosine monophosphate (cAMP). In adult cells, the maximal response to microcystin was considerably less than that obtainable with forskolin or cAMP. After achieving a maximal response with microcystin, the addition of forskolin increased ICa further in adult cells but elicited no additional response in newborn cells. The treatment of cells with 0.1 microM isoproterenol, a concentration approximately equal to that required for a half-maximal response, strongly potentiated the effect of microcystin in newborn cells, but not in adult cells. We propose that newborn rabbit heart cells compared with adult rabbit heart cells have a greater level of protein phosphatase activity (perhaps combined with a somewhat greater kinase activity), a greater proportion of the protein phosphatase activity in the form of protein phosphatase type 1 (which is inhibited by isoproterenol) and a greater dependence on the inhibition of protein phosphatase as a mechanism of action of isoproterenol, compared with the increase in kinase activity on calcium channels.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0031-6768
pubmed:author
pubmed:issnType
Print
pubmed:volume
427
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
389-98
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed-meshheading:7971137-Animals, pubmed-meshheading:7971137-Animals, Newborn, pubmed-meshheading:7971137-Calcium Channels, pubmed-meshheading:7971137-Cyclic AMP, pubmed-meshheading:7971137-Ethers, Cyclic, pubmed-meshheading:7971137-Female, pubmed-meshheading:7971137-Forskolin, pubmed-meshheading:7971137-Heart, pubmed-meshheading:7971137-Heart Ventricles, pubmed-meshheading:7971137-Isoproterenol, pubmed-meshheading:7971137-Male, pubmed-meshheading:7971137-Membrane Potentials, pubmed-meshheading:7971137-Microcystins, pubmed-meshheading:7971137-Myocardium, pubmed-meshheading:7971137-Okadaic Acid, pubmed-meshheading:7971137-Patch-Clamp Techniques, pubmed-meshheading:7971137-Peptides, Cyclic, pubmed-meshheading:7971137-Phosphoprotein Phosphatases, pubmed-meshheading:7971137-Phosphoric Monoester Hydrolases, pubmed-meshheading:7971137-Rabbits
pubmed:year
1994
pubmed:articleTitle
Developmental changes in the actions of phosphatase inhibitors on calcium current of rabbit heart cells.
pubmed:affiliation
Todd Franklin Cardiac Research Laboratory, Department of Pediatrics, Emory University, Atlanta, GA 30323.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S.