Linked Life Data

2793847

Source:http://linkedlifedata.com/resource/pubmed/id/2793847

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
29
pubmed:dateCreated
1989-11-17
pubmed:abstractText
Changes of cytosolic free Ca2+ [( Ca2+]i) in response to receptor activation were studied at the single cell level by using digital imaging fluorescence microscopy of fura-2-loaded primary cultured hepatocytes. In response to phenylephrine and vasopressin, individual hepatocytes displayed dose-dependent oscillations of [Ca2+]i similar to those observed in aequorin-injected hepatocytes by Woods et al. (Woods, N. M., Cuthbertson, K. S. R., and Cobbold, P. H. (1986) Nature 329, 719-721). With increasing agonist concentration, the frequency of oscillations increased and the latent period decreased. For a given cell, peak [Ca2+]i was independent of applied agonist concentration. However, there was considerable variation from cell to cell in the absolute value of peak [Ca2+]i. There was also marked intercellular heterogeneity in the latency, frequency, and overall pattern of the Ca2+ responses. Such asynchronous responses can be explained in part by the apparent differential agonist sensitivity of individual cells for latency and frequency. At high doses, phenylephrine maintained an oscillatory pattern, whereas vasopressin produced a complex mixture of spiking and sustained [Ca2+]i responses. Vasopressin and phenylephrine also displayed differently shaped [Ca2+]i oscillations at submaximal doses, due primarily to a slower rate of decay with vasopressin. Despite the large cell-cell variation in the patterns of [Ca2+]i oscillations, successive readditions of the same agonist elicited identical cell-specific patterns of oscillation. In the absence of extracellular Ca2+ the frequency but not the magnitude of [Ca2+]i oscillations was decreased. Buffering of [Ca2+]i by increasing the fura-2 load of single hepatocytes also decreased the frequency of oscillations without affecting the peak Ca2+ level. These data provide further support for the importance of frequency modulation in agonist-induced Ca2+ responses and suggest that Ca2+ itself plays an important role in regulating the frequency of [Ca2+]i oscillations. Furthermore, the data demonstrate a broad heterogeneity in hepatocyte [Ca2+]i oscillations which may underlie the nonoscillatory responses of cell populations.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
264
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
17131-41
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Characterization of cytosolic calcium oscillations induced by phenylephrine and vasopressin in single fura-2-loaded hepatocytes.
pubmed:affiliation
Department of Pathology and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S.