The growth control and response to extracellular adenosine stimulation in pig aortic smooth muscle cells cultured in different conditions were tested. Cells that were cultured in medium containing 10% fetal bovine serum were proliferative. Cells were quiescent when cultured in a chemically defined medium, which contains 10$\sp{-6}$ M insulin, 5 $\mu$g/ml transferrin, and 0.2 mM ascorbate. The response to adenosine stimulation in the quiescent cells was lower than that observed in cells cultured in serum-containing medium. Both the cell growth index and the response to adenosine of cells cultured in defined medium were reversible after replacing the medium with 10% fetal bovine serum-containing medium. These results suggested that the cells in defined medium were healthy and were capable of modulating cellular metabolism depending on culture conditions. The role of phosphodiesterase (PDE) in modulating cellular cAMP levels was also studied in pig aortic smooth muscle cells cultured in serum-containing medium. Three different PDE isozymes were separated by Mono Q HPLC chromatography and identified by selective PDE inhibitors. They are calmodulin-dependent, cGMP-inhibited, and rolipram-sensitive PDEs. Each of the isozymes was differentially distributed in subcellular fractions. These three PDE isozymes present in smooth muscle cells play an important role in modulating cellular cAMP levels after adenosine stimulation. The differential importance of each isozyme may depend on cellular cAMP levels.
| Identifer | oai:union.ndltd.org:UMASS/oai:scholarworks.umass.edu:dissertations-8216 |
| Date | 01 January 1991 |
| Creators | Xiong, Yimin |
| Publisher | ScholarWorks@UMass Amherst |
| Source Sets | University of Massachusetts, Amherst |
| Language | English |
| Detected Language | English |
| Type | text |
| Source | Doctoral Dissertations Available from Proquest |
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