Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0029463 (osteosarcoma)
 16,637 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Intracellular microelectrode measurements were made on a well-characterized osteoblast-like clonal cell line isolated from a rat osteosarcoma. In serum-free medium, stable membrane potentials of -42 +/- 9 mV (SD, n = 190) were recorded. Ion substitution experiments suggested that this membrane potential is primarily a Na+/K+ diffusion potential. Input resistance was correlated strongly with colony size, ranging from 49 +/- 18 M omega (SD, n = 14) for colonies of 1-3 cells, to 4 +/- 4 M omega (SD, n = 164) for colonies of 100 or more cells. These results are consistent with the existence of low resistance intercellular junctions. Application of the carboxylic calcium ionophore A23187 by pressure microejection onto the cell surface resulted in a transient hyperpolarization and concomitant decrease in input resistance. Both these effects are consistent with an increased K+ conductance. Ion substitution experiments demonstrated that the degree of hyperpolarization was dependent on the external concentration of both K+ and Ca2+. Quinine, a blocker of Ca2+-activated K+ channels, inhibited the ionophore-induced hyperpolarization in a dose-dependent manner. It was concluded that these cells exhibit a Ca2+-activated K+ conductance.
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PMID:Electrophysiology of a clonal osteoblast-like cell line: evidence for the existence of a Ca2+-activated K+ conductance. 643 42